Question

Find the m∠BAC, if m∠DEC = 45° and m∠EDC = 65°.

A 50 degrees
B 60 degrees
C 70 degrees
D 80 degrees

Answer 1

70 Degrees

Explanation:

Find the m∠BAC, if m∠DEC = 45° and m∠EDC = 65°.

50°

60°

70°

80°

Odyssey

Answer 2

Answer: C - 70°

Proof: Since ED || CB and CD || AB, then
∠ACB = ∠CED (corresponding angles along parallel lines; BC || DE)
Also, ∠DCE = ∠BAC (corresponding angles along parallel lines; AB || CD)

Thus, ∠BAC = ∠DCE = 180 - (45 + 65) = 70° (ie C)