What is the area of to the nearest tenth of a square centimeter? Use special right triangles to help find the height.

This is a 30º-60º-90º triangle where the length of the side across from the 30º angle = 5 cm.

 

So...the length of the side across from the 60º angle = 5√3 cm.

 

area of triangle = (1/2)(base)(height)

area of triangle = (1/2)(5)(5√3 )  cm²

area of triangle = 12.5√3           cm²

area of triangle ≈ 21.7               cm²