Answer:
AB = 15
m∠A = 53.1°
m∠B = 36.9°
Explanation:
From the picture attached,
By Applying Pythagoras theorem,
AB² = AC² + BC²
AB² = 9² + (12)²
AB² = 81 + 144
AB = √225
AB = 15
tan(B) =
![\frac{\text{Opposite side}}{\text{Adjacent side}}](https://img.qammunity.org/2021/formulas/mathematics/high-school/n381isx29cf0huaq8101v492uma9k8sz3q.png)
=
![(12)/(9)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/r7nm58fjdjz287yj9uebtky7citchqqp0a.png)
= 1.3333
B =
![\text{tan}^(-1)(1.3333)](https://img.qammunity.org/2021/formulas/mathematics/high-school/ko75hi0fkcdklxo9r4pr46usgs24b1wsro.png)
= 53.13
≈ 53.1°
Since, m∠A + m∠B + m∠C = 180°
m∠A + 53.1° + 90° = 180°
m∠A = 180°- 143.1°
= 36.9°