Answer:
x = 10
Explanation:
The radius of the circle is shown as x. That will be the measure of the hypotenuse of the right triangle with sides 6 and 8. You recognize these side lengths as having the ratio 3:4 (with a multiplier of 2), so you know that the hypotenuse will be 5 with a multiplier of 2. That is, x = 10.
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In case you're not familiar with a 3-4-5 right triangle, you can verify that the hypotenuse is 5 units using the Pythagorean theorem:
c = √(a^2 +b^2) = √(3^2 +4^2) = √25
c = 5
Multiplying the values by 2 gives ...
x = √(6^2 + 8^2) = √(36 +64) = √100
x = 10