Answer:
C. 5
Step-by-step explanation:
OXA is a 3-4-5 right triangle, so the circle radius is OA = 5.
_____
By the Pythagorean theorem,
AO² = OX² +AX² = 3² +4² = 9 +16 = 25
AO = √25 = 5 . . . . circle radius
_____
<em>Comment on Pythagorean triples</em>
The triple of integers (3, 4, 5) is the smallest triple of integers that satisfies the relation of the Pythagorean theorem. The next smallest set is (5, 12, 13). These, and a few other similar triples such as (7, 24, 25) and (8, 15, 17) are often used in algebra and geometry problems because they make the numbers work out nicely. It is worthwhile to learn to recognize these.
