Squares in a Rectangle

Geometry Level 1

There are 7 smaller squares inside the large rectangle above.

If the green square has side length 1 and the brown square has side length 2, what is the area of the rectangle?


The answer is 63.

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33 solutions

Brock Brown
Mar 27, 2015

Let A A be the total area.

animation animation A = ( 5 + 4 ) × ( 4 + 3 ) = 63 \implies A = (5+4) \times (4 + 3) = \boxed{63}

Nice image! The gif makes it so obvious how to calculate the lengths :)

Chung Kevin - 6 years, 2 months ago

why (4+3)? what about this A = (5 + 4) x ( 2 + 2 +2 + 3) = 81 ?

Siti Saudah - 4 years, 10 months ago

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Because instead of multiplying length by width you'd be multiplying length by length.

Brock Brown - 4 years, 10 months ago
Otto Bretscher
Mar 24, 2015

In the bottom right we have a square of size 3 × 3 3\times3 , in the bottom left a 4 × 4 4\times4 and in the upper left a 5 × 5 5\times5 . Thus the area of the rectangle is ( 3 + 4 ) × ( 4 + 5 ) = 63 (3+4)\times(4+5)=63 .

Nice way to quickly get the lengths.

Chung Kevin - 6 years, 2 months ago

The bottom right rectangle is only assumed to be a square. Should've been explained in a clear way, but nice solution.

Henrique Formigomi Morais - 6 years, 2 months ago

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I've added that into the question. I forgot to say that they were all squares.

Chung Kevin - 6 years, 2 months ago

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Brilliant.org thanks you for that :)

Henrique Formigomi Morais - 6 years, 2 months ago

They're not all squares. There is a 6x2 rectangle in the upper right hand corner

Adam Kaffen - 6 years, 2 months ago

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@Adam Kaffen Maybe say something like "In the figure above, the large rectangle contains (or consists of) seven squares." English is my third language... ;)

Otto Bretscher - 6 years, 2 months ago
Donald Dkhar
Mar 25, 2015

Extends all the lines and color them......Visualization is much easier

brown square=12 i.e area of brown=(2 2) 12=48 green square=15 i.e area of green=(1 1) 15=15 Therefore, area of the whole rectangle is =48+15=63

Oh, that's a nice way to count them all!

Chung Kevin - 6 years, 2 months ago

I hope this explains everything. :)

That's a very detailed image! Thanks!

Chung Kevin - 6 years, 2 months ago
Anubhav Sharma
Mar 26, 2015

The shape can be divided into following shape.

There are 12 big squares of area 4.

There are 15 squares of area 1.

Total Area = 12 * 8 + 15 * 1

                     =48 + 15

                     = 63

Great image to help explain how to count the lengths

Chung Kevin - 6 years, 2 months ago

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Thanks Sir!!!

Anubhav Sharma - 6 years, 2 months ago
Eric Osborn
Mar 24, 2015

There's one green square (1x1) and two squares congruent with the orange square (2x2). Bottom right square's side is the side of the green and the orange added together and a square so it's (3x3). Same process to get the bottom left square at 4x4 and 5x5 for the top left square. 25+16+9+4+4+4+1=63

Thanks for the explanation!

Chung Kevin - 6 years, 2 months ago
Abdulahi Abdinur
Mar 24, 2015

(2 + 2 + 2 + 3)*(3 + 4) = 63 2 is the base of the upper square, and you have 3 of them. The base of the bottom right square is 2 + 1. You multiply by the base of the bottom right square plus the base of the lower left corner, which is 3 + 1

Nicely done :)

Chung Kevin - 6 years, 2 months ago
Dladla Arthur
Mar 29, 2015

long side = 2*3 =6+3=9

breath side=3+4=7

therefore area= 9*7 = 63

Asma Rasheed
Mar 27, 2015

Area= length × breadth

=[(2+2+2+3)×(3+4)]

=9×3

=63 Answer

Daffa Budiman
Mar 26, 2015

( 6 + 3 ) × ( 4 + 3 ) = 9 × 7 = 63. Its easy if you DRAW first

It's much easier when you draw it first :)

Chung Kevin - 6 years, 2 months ago
Charles Grenier
Mar 24, 2015

(1x1)+3(2x2)+(3x3)+(4x4)+(5x5)=63

How did you get those lengths?

Chung Kevin - 6 years, 2 months ago

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It's said in the problem. One square have a length of 1. A second square have a length of 2. It's juste logic. You see that there is a square that you can combine the square of 1 and the square of 2 to arrive to the length of 3, etc.

Charles Grenier - 6 years, 2 months ago
Shawn Thomas
Mar 29, 2015

2 X 2 = Area of the brown box and the adjacent squares have equal sides so it becomes 4 X 3 (as the three adjacent squares have equal sides). The length of the sides increases from 1<2<3<4<5 which could be interpreted from the diagram so when you add 12 + 9 + 16 + 25 + 1(area of the squares) you get 63

Good approach!

Chung Kevin - 6 years, 2 months ago
Souvik Guha
Mar 26, 2015

Just looking like a square is not definitive proof that it is a square! So i think picture should be more explained and specified.

فكر وغير
Mar 24, 2015

7*9=63 sq units

How / why?

Chung Kevin - 6 years, 2 months ago

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He means that the breadth is 7 and the length is 9 so the area is 63

tanveen dhingra - 6 years, 2 months ago
Gamal Sultan
Mar 24, 2015

5 X 5 + 2 X 2 + 2 X 2 + 2 X 2 + 3 X 3 + 4 X 4 + 1 X 1 = 63

Alkis Piskas
Oct 22, 2018

1) KC = IJ = IK = 1 + 2 = 3

2) DK = EF = FK = FI + IK = 1 + 3 = 4

DC = KC + DK = 3 + 4 = 7 (smaller side of rectangle)

BC = 3 * 2 + JC = 3 * 2 + KC = 3 * 2 + 3 = 9 (larger side of rectangle)

Area of the triangle = DC * BC = 63

Denis Schüle
Jun 3, 2018

given the way, the squares are placed around the 1cm square, we can see easily that: let a be the 2 cm square. and b,c,d the other squared, ordered by size.

then it's obvious that the sidelength of b, the next biggest square , is side length of a plus the 1 cm of the 1 cm square. same goes for b and c: c length=b length+1 d length=c length+1

we find that their lengths are: a=2,b=3,c=4,d=5

then we just need to square all the lengths and add them up, keeping in mind thatt there are 3 2cm squares: 1^2+2^2+2^2+2^2+3^2+4^2+5^2=63

Ahsim Nreiziev
Mar 25, 2018

The square at the bottom right has sides of 2 + 1 = 3 2 + 1 = 3 . From this we can also deduce that the square at the bottom left has sides of 3 + 1 = 4 3 + 1 = 4 .

Thus, the sides of the rectangle are 3 × 2 + 3 = 9 3 \times 2 + 3 = 9 and 3 + 4 = 7 3 + 4 = 7 . The area of the rectangle can now easily be calculated as 9 × 7 = 63 9 \times 7 = \large \color{#20A900}{\boxed{63}}

Mike Holden
Nov 18, 2017

Area of rectangle = right hand edge x bottom edge. = (2 + 2 + 2+ 3) x (3 + 4) = 63

Picture solution

J Chaturvedi
Apr 9, 2016

A=(5+2)×(6+3)=63

Akshay Kumar
Apr 12, 2015

Area of a rectangle=(length x breadth) So just count the number of boxes and extrapolate to estimate the length of each side and hence the area of the rectange which is (7[vertical] x 9 [horizontal]=63)

Area=(4+3)*(2+2+2+3)=63. Here 7 is the length which is obtained from the length of the sides of the squares......and 9 is the breath.....it is also obtained from the length of the sides of the squares and thus area is obtained.

it's 7x9=63 :)

Vertical distance=(2+2+2+3) and Horizontal distance (3+4). So, (2+2+2+3)×(3+4)=9×7=63

Abu Kausar
Mar 29, 2015

Length is (2+2+2+3) and width is (3+4). So area of rectangle is 9X7=63

4+4+4+1+9+16+25=63

Since the brown square has a side length of 2, and the green square a side length of 1, it follows that the largest square has a side length of 5. Similarly, adding the sides of brown and green gives us a side of 3 for the bottom - right square. Thus, the rectangle's width is 7, and the height 9. The total area therefore being 7 × 9 = 63

L = 2X3+2+1= 9, W = 3+2x2 = 7, Area = LxW = 9x7 = 63

Rachel Plucker
Mar 29, 2015

The green has an area of 1, the brown has an area of four. There are three of those size, so 12 as total area. The big one has an area of 25, below it, 16, beside that, 9. Add it all up to 62

Med Bel
Mar 28, 2015

(2+2+2+3)x(3+4)=63

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