Engineering Board Exam Reviewer · Circles · medium

Find the radius of the circle with center (1,2) that is tangent to the line 3x+4y-20=0.

  1. 9
  2. 3.6
  3. 6.2
  4. 1.8

Answer

D. 1.8

Solution

r= |3(1)+4(2)-20|sqrt(32+42)=9/5=1.8.

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