(1) A circle centered at P with radius 10 and a circle centered at Q with radius 8 are externally tangent. Find PQ.

(2) How many common external tangents do two circles have?

Guest Sep 17, 2021

#1**0 **

*(1) A circle centered at P with radius 10 and a circle centered at Q with radius 8 are externally tangent. Find PQ.*

If you'll draw this, you'll easily see that it's the sum of the two radii, namely 10 + 8 = **18**

*(2) How many common external tangents do two circles have?*

You didn't say if this is specifically in reference to the two circles in (1). Well, anyway:

If two circles are overlapping, they can have **2** common tangents.

If two circles are externally tangent, they can have **3** common tangents.

If two circles are some distance apart, they can have **4** common tangents.

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Guest Sep 17, 2021