Answer:
48) x = 15
49) x = 9
50) x = 17
Step-by-step explanation:
In each case, the product of lengths from the intersection point to the circle (near, far intersection points) is a constant. In the case of a tangent, the two intersection points with the circle are the same point, so the product of the lengths is the square of the length of the tangent.
48) 18^2 = 12(12 +x)
x +12 = 18^2/12
x = 27 -12
x = 15
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49) 12·6 = 8·x
x = 12·6/8
x = 9
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50) 9·(9+21) = 10·(10 +x)
9·30/10 = 10 +x
x = 270/10 -10
x = 17
