**Step-by-step explanation:**

use cosine rule

c^2 = b^2 + a^2 - 2ab(cos)c

#15)

answer is B. 3

3 friends didn't visit zoo

Given the height of the ball at time, t is modeled by:

h(t)=100t-16t^2

the maximum height will be found as follows:

at maximum height:

h'(t)=0

thus given h(t), the derivative will be:

h'(t)=100-32t=0

solving for t we get

t=100/32

thus the time taken for the ball to reach maximum height is t=100/32. Hence the maximum height will be:

h(100/32)=100×100/32-16×(100/32)²

=156.25 ft

126-27 = 99, hope this helps