← All lessons

Power of a Point (Easy)

AMC 10 Q1–8 depth — contest entry, not school drills.

Power of a Point: core idea

Intersecting chords.

Example problem: hint and answer

Two chords intersect inside a circle: segments are 33 and 88 on one chord, 44 and xx on the other. Find xx.

Hint: 3⋅8=4⋅x3\cdot 8=4\cdot x. Answer: 6.

Practice (9 problems — type your answers)

  • 1. Intersecting chords: segments 22 and 1212; on the other chord 33 and xx. Find xx.

  • 2. From external point, tangent length 66 and secant external segment 44. Find whole secant length.

  • 3. Chords intersect: 5⋅x=4⋅105\cdot x=4\cdot 10. Find xx.

  • 4. Tangent 88, external secant segment 44. Whole secant?

  • 5. Intersecting chords: segments 66 and 66; other chord 44 and xx.

  • 6. From external point, tangent length 66 and whole secant length 99. Find the external secant segment.

  • 7. Chords: 22 and 1818; other side 66 and xx.

  • 8. Tangent 99, external segment 33. Whole secant?

  • 9. Intersecting chords: 77 and 44; other chord xx and 22.

Power of a Point Practice Problems — Easy