Answer:A. 3 InchesStep-by-step explanation:To find the radius of the circle, we need to use the Pythagorean Theorem.a²+b²=c²a = r inchesb = AD or 4 inchesNow to get the value of c, we need to consider the measurement of the line AD. The sum of line AD and line DC will be the value of the hypotenuse.c = r + 2 inchesNow that we have our variables, let's plug them in.a² + b² = c²r²+ 4² = (r + 2)²Now we need to use the FOIL method for r + 2.r² + 16 = (r + 2)(r + 2)r² + 16= r² + 2r + 2r + 4r² + 16 = r² + 4r + 4Now we can remove r² by subtracting both sides by r², leaving us with:16 = 4r + 4Now we subtract 4 from both sides.4r = 12Now we divide both sides by 4.r = 3 inches