Answer: √13.
- A √11
- B √13
- C 5
- D √26
Correct answer: B. √13
Explanation: The circle is x² + y² − 4x − 6y = 0 with centre (2, 3), radius √(4 + 9) = √13.
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