The circumference of one coin is 8.03 cm. the circumference of
another coin is 0.33 cm smaller.

a. what is the first step to find the diameter of the smaller coin?

find the radius of the smaller coin. find the diameter of the larger coin.
find the circumference of the larger coin.
find the circumference of the smaller coin.

b. find the diameter of the smaller coin.
use for 22/7 for pi.

Ok, this looks like a law of sine problem. You are given two side lengths and their opposite angles. The hypotenuse is 12 and the measure of its opposite angle is 90 (right triangle). One of the legs is 7 and you are asked to find its opposite angle: y.

To set this up using law of sines, use the formula: sin A over a = sinB over b
 (A and B are the angles while a and b are the side lengths).
Plug in the values you are given and you have: sin 90 over 12 = sin y over 7

You follow me so far?