1. ## Rhombus Pythagorean!

Each side of a rhombus measures 12 in. If one diagonal is18 in. long, how long is the other diagonal?

So what I did is. Constructed a rhombus. Made each side 12 in and made a diagonal of 18. I make another diagonal and so I get 4 right angles

I choose 1. I have 12 as c^2 and 9 as a^2 now. I need to find B^2

9^2 = 81 + b^= 144

b = 63

correct answer is --- > 6√7

2. ## Re: Rhombus Pythagorean!

I'm not sure what the question is, your reasoning is correct. Just remember that the b you found is only half the length of the diagonal.
b = sqrt(63) = sqrt(9 * 7) = 3*sqrt(7)
2*b = 6 sqrt(7)

3. ## Re: Rhombus Pythagorean!

Just to find the length of the other diagonal.
Multiplying 3*sqrt(7) by 2 equals the correct answer. But Whats the reasoning for multiplying 3*sqrt(7) by 2?
The correct answer is 6sqrt(7) but I didn't seem to get it.

4. ## Re: Rhombus Pythagorean!

Originally Posted by Cake
Just to find the length of the other diagonal.
Multiplying 3*sqrt(7) by 2 equals the correct answer. But Whats the reasoning for multiplying 3*sqrt(7) by 2?
The correct answer is 6sqrt(7) but I didn't seem to get it.
The diagonals of a rhombus bisect one another at right angles.
Thus you found only one-half of its length. That is why we multiply by two.