Answer: |OP|² - r².
- A |OP|² - r²
- B |OP| - r
- C r² - |OP|²
- D |OP| + r
Correct answer: A. |OP|² - r²
Explanation: For any chord through P meeting the circle at A,B: PA×PB = |OP²−r²|. Power is defined as OP²−r² (signed): positive if P is external, negative if internal, zero if P lies on the circle. Ans: |OP|²−r².
Three standard 3D solids and their key formulas: a cylinder's volume scales with the full height, a cone's volume is exactly one-third of the cylinder with the same base and height, and a sphere's volume and surface area both follow distinct r-based formulas worth memorising separately.
Concept context
Perimeters, areas, and volumes of 2D and 3D shapes