Question

Write expression that gives the required unknown value.

1. If a = 8 and c = 12, find B.

Answer:

2. If a = 13 and B = 16°, find c.

Answer:

3. If A = 15° and c = 37, find a.

Answer:

Answer 1

1_________________

$cosB = \frac{a}{c}\\ cosB = \frac{8}{12}\\ B = arccos(\frac{8}{12})$

2_________________

$cosB = \frac{a}{c} \\ c = \frac{a}{cosB}\\ c = \frac{13}{cos16°}$

3_________________

$sinA =\frac{a}{c}\\ a = c×sinA\\ a = 37×sin15°$