Solve the following triangle, rounding answers to the nearest tenth if necessary. In ∆RST, r = 12.6 m, s = 11.5 m, and t = 13.2 m

Question

This is a right triangle, I believe.

Answer 1

By cosine law cosT = (r² + s² - t²)/(2rs) = (12.6² + 11.5² - 13.2²)/(2·12.6·11.5) = .402933;

T = cos^-1(.402933) = 66.2°.

By sine law sinS = s·sinT/t = 11.5sin66.2°/13.2 = .7971; S = sin^-1(.7971) = 52.9°

R = 180° - (T + S) = 180° - (66.2° + 52.9°) = 60.9°