## xRAWRRx3 3 years ago Please help a desperate freshman. :( Quadrilateral ABCD is a rhombus with an area of 600 square inches and diagonal AC = 30. What is the perimeter of quadrilateral ABCD?

1. AccessDenied

2. AccessDenied

Now, I think we can find the other diagonal's length using the formula for the area of this rhombus. Do you know the equation for it?

3. xRAWRRx3

i found out that its area = diagonal 1 times diagonal 2 over 2 so i got the other diagonal equals 40. what do i do after that?

4. AccessDenied

We can use some right triangle magic since rhombuses have the cool property that their diagonals intersect at right angles and also bisect each other. :) |dw:1338083233182:dw| So, if we take half of each diagonal, we get a right triangle with legs of those values and a hypotenuse of the side of the rhombus. All we have to do is find that hypotenuse, and the rest should be pretty easy -- adding all four equal sides of the rhombus together.

5. xRAWRRx3

OMG, THANK YOU :) THAT REALLY HELPED A LOT X)

6. RaphaelFilgueiras

|dw:1338083360007:dw|

7. AccessDenied

You're welcome! :D Geometry problems really like to do these sorts of things, spotting right triangles in different situations. :P

8. RaphaelFilgueiras

alpha =pi/2

9. xRAWRRx3

I was just confused because I didn't know what the formula to the area of a rhombus was x_x but after that, I was just over thinking things LOL so thank you :)