Question

In triangle abc, ab=7 root3cm, ac=14cm, bc=7cm find angle b

Answer 1

Answer:

∠b = 90°

Step-by-step explanation:

Δabc  

ab = 7√3  cm

ac = 14 cm

bc = 7 cm

∠b = ?

side opposite to √b = ac

ac² = ab² + bc² - 2(ab)(bc)Cosb

14² = (7√3)² + 7² - 2(7√3)(7)Cosb

196 = 147 + 49 - 2(7√3)(7)Cosb

196 = 196 - 2(7√3)(7)Cosb

2(7√3)(7)Cosb = 0

cosb = 0

b = 90°  ( as Cos 90° = 0)

Answer 2

Answer:

90 is the correct answer hope