Red Area

Geometry Level 2

What percentage of the area of the rectangle is the red Area equals to? (Answer should be rounded to the nearest whole number)

45 \%

40 \%

52 \%

60 \%

50 \%

2 solutions

Vinayak Srivastava
Jun 12, 2020

Total area $=6\times4=24$

Red area $=\dfrac{3\times 2}{2}+\dfrac{2\times2}{2}+\dfrac{2\times 2}{2}+\dfrac{3\times 3}{2}+\dfrac{2\times 1}{2}=3+2+2+4.5+1=12.5$

Percentage red $=\dfrac{12.5}{24}\times 100\% =52.08\overline{3}\approx 52\%$

Thank you.

Hana Wehbi - 12 months ago

You're welcome, but thank you for sharing such good problems, your problems are really fun to solve!

Vinayak Srivastava - 12 months ago

Okay, l will do my best to keep it that way.

Hana Wehbi - 12 months ago

Hana Wehbi
Jun 12, 2020

Area of any triangle is : $\frac { base \times height }{2}$

Area of any rectangle is : $length \times width = 6\times 4 = 24$

Thus: $A_1 = \frac{3\times 2}{2}= 3$

$A_2= \frac{ 2\times 2}{2} = 2$

$A_3= \frac{ 2\times 2}{2} = 2$

$A_4= \frac{ 3\times 3}{2} = 4.5$

$A_5= \frac{ 2\times 1}{2} = 1$

$A_{Red}= 3+2+2+4.5+1 = 12.5 \implies \frac{ Red Area }{Total Area} = \frac{12.5}{24} = 52\%$