Question

The length of a diagonal of a square is 7 inches. Find the perimeter of the square.
A. 25 inches
B. 12 inches
C. 19.6 inches
D. 28 inches

Answer 1

Do you know how to set up the equation?

Answer 2

2a^2=7^2

Answer 3

Not quite. You're missing b.
So the equation would look like: \[\large \large a^2 + b^2 = 7^2\]

Answer 4

Now simplify. What would 7^2 become?

Answer 5

49

Answer 6

So it would look like: \[\large \large a^2 + b^2 = 49\]

Answer 7

Since its a square, you can write it as: \[\large \large a^2 + a^2 = 49\] Now what does
a^2 + a^2 give us?

Answer 8

2a^2.

Answer 9

@RPguy @eSpeX

Answer 10

You have worked your equation down to \(2a^2=49\), isolate your \(a^2\) next.

Answer 11

How would you get your \(a^2\) alone?

Answer 12

\[\sqrt{a}^{2}=\sqrt{49}\]

Answer 13

Close, but recall that you have \(2a^2\), so you will need to divide out the 2 before you can take the square root and get 'a'.

Answer 14

\[\sqrt{24.5}=\sqrt{a}^{2}\]

Answer 15

Yes, making 'a' equal to ?

Answer 16

And then you know that the perimeter of a square is equal to \(4a\)

Answer 17

so it will be c

Answer 18

Yes, nice work. :)

Answer 19

thank you :)

Answer 20

You're welcome.