Question

Select the angle that correctly completes the law of cosines for this triangle

Answer 1

Answer:

Option 'B'

Step-by-step explanation:

The law of cosines states that given a triangle with sides a, b, c, then:

$c^{2} =a^{2}+b^{2} -2abcos(y)$ where 'y' is the opposite angle to the side 'c'.

In this case, given that the equation is: $15^{2} =8^{2} + 17^{2} -2(8)(17)cos(y)$ we can clearly see that c=15, and the opposite angle to 'c' is 62 degrees.

The correct option is Option 'B'

Answer 2

ANSWER

B. 62°

EXPLANATION

The cosine rule is given by:

${b}^{2} + {c}^{2} - 2(bc) \cos(A) = {a}^{2}$

where A is the angle that is direct opposite to the side length which is 'a' units.

The given relation is:

$8^{2} + {17}^{2} - 2(8)(17) \cos( - ) = {15}^{2}$

The missing angle should be the angle directly opposite to the side length measuring 15 units.

From the diagram the missing angle is 62°