Number of Rectangles with area 1470?

Geometry Level 3

What is the number of non congruent rectangles, with integer side lengths, and area 1470?


The answer is 12.

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1 solution

Finn Hulse
Feb 13, 2014

First we must prime-factorize 1,470 (remember, we are looking for integers that multiply out to 1,470). We see that 1 , 470 = 2 × 3 × 5 × 7 2 1,470=2 \times 3 \times 5\times 7^{2} . Adding one to all of the powers (refer to this ), and multiplying together gets 24. So 1,470 has 24 integral factors, but that's not how many sets of 2 numbers that multiply to 1,470 there are. So we divide by 2 to find that there are 12 pairs of numbers that multiply to get 1,470.

It's wrong

Sam And anderson - 2 years, 7 months ago

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