Question

Suppose an isosceles triangle ABC has A = 45° and b = c = 4. What is the length of a2?

Answer 1

You can use the Law of Cosines (a^2=b^2+c^2-2bc cosA)

a^2=4^2+4^2-2*4*4*cos45°

a^2=32-32cos45°

a^2=32(1-cos45°)

a=√(32(1-cos45°))

a≈3.06 units (to nearest hundredth of a unit)