An artist wishes to make a sign in the shape of an isosceles

An artist wishes to make a sign in the shape of an isosceles triangle with a 42° vertex angle and a base of 18m. What is the area of the sign?

Solution

base = 18m

since its an isolceles triangle the altitude is the angle bisector

so , we can find altitude by applying tan rule

tan 42/2 = 18/2 / h

h = 23.44

area = 1/2 * base * height

= 1/2 * 18 * 23.44

area of sign = 211 square metres