Question

In triangle ABC m∠A 25 m∠b =55 and c=25 find b round your answer to the nearest tenth

A.10.7
B.12.9
C.48.5
D.20.8

Answer 1

Given are the following:

m∠A = 25

m∠B = 55

c = 25

First, get the value of m∠C by getting the third angle of a triangle. We all know that it should sum up to 180. So we have,

180 - 25 - 55 = m∠C = 100

After getting the value of m∠C and its opposite side is given, we can use the law of sine to find of b

c / m∠C = b / m∠B

25 / sin 100 = b / sin 55 ⇒ substituting the given values to the equation

25(sin 55) / sin 100 = b ⇒ simplify

20.79 = b

b = 20.8 ⇒ answer (D)

Answer 2

Given are the following:
m∠A = 25
m∠B = 55
c = 25

First, get the value of m∠C by getting the third angle of a triangle. We all know that it should sum up to 180. So we have,
180 - 25 - 55 = m∠C = 100

After getting the value of m∠C and its opposite side is given, we can use the law of sine to find of b

c / m∠C = b / m∠B
25 / sin 100 = b / sin 55 ⇒ substituting the given values to the equation
25(sin 55) / sin 100 = b ⇒ simplify
20.79 = b

b = 20.8 ⇒ answer (D)