Answer:
B = 62° , a = 3.7°, c = 7.9 ⇒ the 3rd answer
Explanation:
* In ΔABC
- a, b, c are the lengths of its 3 sides, where
# a is opposite to angle A
# b is opposite to angle B
# c is opposite to angle C
- m∠A = 28°
- m∠C = 90°
- b = 7
- At first lets find measure of angle B
∵ The sum of the measures of the interior angles in a triangle is 180°
∵ m∠B = 180 - (90 + 28) = 180 - 118 = 62°
* m∠B = 62°
* To solve the right triangle we can use the trigonometry functions
- sin∠B = b/c
∵ sin62° = 7/c ⇒ by using cross multiplication
∴ c = 7/sin62 = 7.9
- tan∠A = a/b
∵ tan28° = a/7 ⇒ by using cross multiplication
∴ a = 7 × tan28 = 3.7
∴ The length of the two sides a = 3.7 and c = 7.9 , m∠B = 62°
* B = 62° , a = 3.7°, c = 7.9