∠CFD=60 (all the angles in an equilateral triangle are 60)
#6
∠AFD=150=∠AFB+∠BFC+∠CFD
∴150=∠AFB+35+60
∴∠AFB=55
#7
An isosceles triangle has one unique vertex angle and two equal base angles. All the angles in a triangle add up to 180. We know the base angles (55), so:
180 = ∠ABF + 2(55)
∴∠ABF = 70
#8
∠A=∠AFB = 55 (base angles of an isosceles triangle)
11. An isosceles triangle has one unique vertex angle and two equal base angles. All the angles in a triangle add up to 180. Vertex angle is 18, so the sum of both bases is 180-18=162. Therefore, each base angle is 81.
