In the figure to the right, if AC = 21 and BC = 18, what is the
radius?

Triangle is missing, so i have attached it.

Radius = 10.82

Step-by-step explanation:

From the image attached, the triangle is obviously a right angle triangle and therefore, the missing side (AB) which is the radius can be found via pythagoras theorem.

We are given;

AC = 21

BC = 18

Thus;

|AC|² = |AB|² + |BC|²

21² = |AB|² + 18²

|AB|² = 441 - 324

AB = √117

AB = 10.82

3x + 4y -25 =0 represents the amount of change sianna should recieve