Trigonometry =S.

[Explosions Hurt]

This question is really kind of bugging me o.o

'Find the cross-sectional area of the pitched roof WXY if WX = WY'

The prism is WXY, ignore the different colored lines, I got this image from Google Images. The bottom line is 20m.

[+Moon]

base * height / 2
The area of a triangle!

[SeaBanana]

base * height / 2
The area of a triangle!

Moon has answered youe question

[sockatobi]

Since WX=WY, the base triangle is isosceles. That means that the right triangle made by the height (red line) is a 45-45-90 triangle.

The whole baseline of the prism base is 20, so the base of the right triangle is 10.

Since one leg is 10, and the right triangle is isosceles, the other leg is 10.

Using the 45-45-90 triangle theorem, since the legs are both 10, the hypotenuse is 10√2

(10^2 + 10^2 = 200. √200 = √100 * √2 = 10√2)

Hope I could help.

[etcBro]

You're going to be so freakin happy when you finish Geometry.