Question

Find the measures of angle A and B. Round to the nearest degree.

Answer 1

∠ A = 60° , ∠ B = 30°

Explanation:

using the cosine ratio in the right triangle

cosA =
`(adjacent)/(hypotenuse)` =
`(AC)/(AB)` =
`(7)/(14)` =
`(1)/(2)` , then

∠ A =
`cos^(-1)` (
`(1)/(2)` ) = 60°

the sum of the 3 angles in Δ ABC = 180°

∠ A + ∠ B + ∠ C = 180°

60° + ∠ B + 90° = 180°

∠ B + 150° = 180° ( subtract 150° from both sides )

∠ B = 30°