Question

Solve the triangle. Round your answers to the nearest tenth. A. m∠A=43, m∠B=55, a=16 B. m∠A=48, m∠B=50, a=23 C. m∠A=48, m∠B=50, a=26 D. m∠A=43, m∠B=55, a=20

Answer 1

Answer:

D. m∠A=43, m∠B=55, a=20

Step-by-step explanation:

Given:

∆ABC,

m<C = 82°

AB = c = 29

AC = b = 24

Required:

m<A, m<C, and a (BC)

SOLUTION:

Find m<B using the law of sines:

$\frac{sin(B)}{b} = \frac{sin(C)}{c}$

$\frac{sin(B)}{24} = \frac{sin(82)}{29}$

$sin(B)*29 = sin(82)*24$

$\frac{sin(B)*29}{29} = \frac{sin(82)*24}{29}$

$sin(B) = \frac{sin(82)*24}{29}$

$sin(B) = 0.8195$

$B = sin^{-1}(0.8195)$

$B = 55.0$

m<B = 55°

Find m<A:

m<A = 180 - (82 + 55) => sum of angles in a triangle.

= 180 - 137

m<A = 43°

Find a using the law of sines:

$\frac{a}{sin(A)} = \frac{b}{sin(B)}$

$\frac{a}{sin(43)43} = \frac{24}{sin(55)}$

Cross multiply

$a*sin(55) = 25*sin(43)$

$a = \frac{25*sin(43)}{sin(53)}$

$a = 20$ (approximated)