12. why was the united states concerned about nuclear missiles in cuba? a. the missiles could be used to strike the united states. b. the missiles stopped the united states from invading cuba. c. the missiles would be used to bully other island nations. d. the missiles were unstable and could cause ecological disaster.

angle a = 40.6°

step-by-step explanation:

for any right angle triangle we know the pythagoras theorem reveals

hypotenuse² = height²+base²

by this formula we will calculate the length of hypotenuse

h² = 6²+7²

⇒ h =√36+49 = √85 = 9.22

now from the given triangle sin a = height/ hypotenuse

                                                sin a = 6/9.22 = 0.651

therefore

so angle a = 40.6°