Use special right triangle 45-45-90.

I’m not exactly sure what you need to find, so I’ll help you get the lengths of the sides and, from there, the triangle’s area, if that’s what you’re looking for.

In a 45-45-90 right triangle, the two legs are of equal length, meaning leg a is 4yds and leg b is 4yds.

The hypotenuse equals the length of a leg times the square root of 2, so the hypotenuse is 4 root 2 yds.

That gives you the three side lengths, but if area is what you need, keep reading:

Area of a right triangle, as with any triangle, is A = 1/2•b•h.

In the case of a right triangle, the two legs are the base and height of the triangle, and with this special 45-45-90, those lengths happen to be equal.

Therefore, A = 1/2•4•4.

Solve by simple arithmetic, and you have A = 8 square yards.

Hope I could help!