Eis an option btw but i need work provided plz!

PQ is a radius. QS is tangent to the circle. In this scenario (a radius and a tangent passing through the same point of the radius) the two segments are always perpendicular.

This implies that PQS is a right triangle. We know that PQ = 10 because it's a radius.

Also, we have

because PR is a radius and RS is given.

So, we can derive QS using the pythagorean theorem:

when solving sales tax it's pretty simple because all you do is add everything for a subtotal and multiply your sub total by the tax so i'll use the first as an example your subtotal is 19.96 x0.05 to get 0.99 <-- your sales tax and your final total with tax to be 20.96