If △ ABC is known, ∠ C = 90, the right triangle can be solved under the following conditions: 1. If a = 20, C = 20, root sign 2, find ∠ B 2. If C = 30, a = 60, find a 3. Given B = 15. A = 30, find a

If △ ABC is known, ∠ C = 90, the right triangle can be solved under the following conditions: 1. If a = 20, C = 20, root sign 2, find ∠ B 2. If C = 30, a = 60, find a 3. Given B = 15. A = 30, find a

1. B & # 178; = lower C & # 178; - A & # 178; = 400, so B = 20. Because a = B, it is an isosceles right triangle, ∠ B = 45 degree
2. Sin ∠ a = A / C = sin60?, so a = C · sin60? = 15 √ 3
3. Cos ∠ a = B / C = cos30 °, so C = B / cos30 ° = 10 √ 3, and because a & # 178; + B & # 178; = C & # 178;, a = √ C & # 178; - B & # 178; = 5 √ 3