Question

61. Name the pair of adjacent acute angles.

a. ZCFB, LBFA
b. ZDFC, ZCFA
c. ZDFB, ZBFE
d. ZDFE, ZBFA

Answer 1

a) ∠CFB, ∠BFA

Explanation:

Acute angles are angles < 90°

AD is a straight line

⇒ ∠CFD + ∠CFB + ∠BFA = 180

⇒ 90 + ∠CFB + 50 = 180

⇒ 140 + ∠CFB = 180

⇒ ∠CFB = 180 - 140

⇒ ∠CFB = 40

∠CFB and ∠BFA are adjacent angles

∠CFB = 40

∠BFA = 50

Both are less than 90°

∴ ∠CFB and ∠BFA are adjacent acute angles