Question

In ΔABC, if a = c = 16 centimeters and m∠B = 85°, what is b to two decimal places? . . 16.56 centimeters. . . 21.62 centimeters. . . 24.48 centimeters. . . 28.86 centimeters. .

Answer 1

Since we are to find B and given only the lengths of the adjacent sides and the opposite angles, use Law of Cosines to answer the question above. This law is expressed as follows,
                                     b² = a² + c² - 2ac x (cos B)
Substituting,
                                 b² = 16² + 16² - 2(16)(16) x (cos 85°)
The value of b is approximately equal to 21.62 cm.