Area for a circle is . We will fill in each area and then solve for the radius. and . ∴ and r = 13. For b, and . , ∴ r = 17. For c, , and . ∴, and r = 11. For d, , and . ∴, so r = 25. And there you have it!
First, you would plug in the numbers for y and r. Therefore, your equation should now be 5 = 9x + 24. Now you would put like terms on the same side. It now then look like -19 = 9x. You divide by 9 to get the x by itself. The answer should be x = -19/9.