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AB is tangent to circle D. Find the value of x.

AB is tangent to circle D. Find the value of x.-example-1
User Somejkuser
by
6.6k points

1 Answer

3 votes

Answer:

c 15

Explanation:

Tangent AB is tangent to circle D at point A. The angle made by a tangent to a circle and a radius of the circle at the point of tangency is a right angle. That means that angle is a right angle, and triangle ABD is a right triangle.

We can use the Pythagoren theorem.

a^2 + b^2 = c^2

x^2 + 20^2 = (x + 10)^2

x^2 + 400 = (x + 10)(x + 10)

x^2 + 400 = x^2 + 10x + 10x + 100

400 = 20x + 100

20x = 300

x = 15

User Gone
by
7.5k points
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