Question

Part B.

Describe two different ways you could find measure of CFD. What is the measure of

this angle?

Answer 1

∠CFD = 60°

Explanation:

Along line CE:

∠AFE + ∠AFB + ∠BFC = 180° (sum of angles on a straight line)

(7x + 4) + (8x + 6) + (6x + 2) = 180

collecting alike terms:

7x + 8x + 6x + 4 + 6 + 2 = 180

21x + 12 = 180

21x = 168

x = 8°

We could find the measure of CFD using:

a) Along line AD:

∠AFB + ∠BFC + ∠CFD = 180° (sum of angles on a straight line).

(8x + 6) + (6x + 2) + ∠CFD = 180

14x + 8 + ∠CFD = 180

∠CFD = `180 - (14x + 8)

∠CFD = 172 - 14x

b) ∠CFD = ∠AFE (vertical opposite angles are equal)

∠CFD = 7x + 4

To find value of ∠CFD, substitute x = 8

∠CFD = 7(8) + 4

∠CFD = 60°