A square has a diagonal length of 39 inches. What is the value of any side of the square?

Question

anonymous · Answer

$$c^2=a^2+b^2$$ where c is the diagonal length (39 inches)  and a=b since it is a square

anonymous · Answer

$$c^2=b^2+b^2$$$$39^2=2b^2$$$$1521=2b^2$$$$760.5=b^2$$$$b=27.58$$

binary3i · Answer

just divide the digonal with square root of 2 and it will give the length of the side

anonymous · Answer

but what do you mean?
(binary3i)

anonymous · Answer

Zed, first reply is consistent to Pythagoras theorem which is again consistent to the cosine rule ...

anonymous · Answer

zed's*

anonymous · Answer

$$\Large \begin{array}{l}
{c^2} = {a^2} + {b^2}\
{a^2} = {b^2}\
{c^2} = 2{a^2}\
{a^2} = \frac{{{c^2}}}{2}\
a = \frac{c}{{\sqrt 2 }}
\end{array}$$

anonymous · Answer

Is what I think binary meant.

binary3i · Answer

yes

anonymous · Answer

so the answer is 15?

anonymous · Answer

Zeds answer was correct 27.58

anonymous · Answer

my answer choices are 4in, 12in, 15in, and 16in.

anonymous · Answer

2*4^2 = 32, 2*12^2 = 288, 2*15^2 = 450, 2*16^2 = 512.

39^2 = 1521.

anonymous · Answer

So either I'm misunderstanding something fundamental, or there's some wrong information here?

anonymous · Answer

ya wrong info somewhere

anonymous · Answer

ok..its a square and basically from one corner to another corner its 39 inches. And i need to find the length of any side of the square.

anonymous · Answer

|dw:1325487443162:dw|
Is this right? Where c = 39?