Question

Find a.
Round to the nearest tenth:

Answer 1

That's 1.8.

The first thing you have to do find the missing angle. Use it instead of the 15. Once you find the missing angle which is 60, you'll be able to get the right answer. Just follow the formula.

Answer 2

You first need to find the last angle measurement which is
60 because 60+15+105= 180

Sin60 Sin105
——— = ———— Cross multiply
a 2

Sin60 * 2 = Sin105*a

1.7 = Sin105*a Divide both sides by sin105

1.79 = a

1.8 ≈ a