18M.1.SL.TZ1.T_14

pestleMathematicsAISLPaper 118M· sl-3-1-3d-space-volume-angles-midpointssource ↗

A solid right circular cone has a base radius of 21 cm and a slant height of 35 cm.
A smaller right circular cone has a height of 12 cm and a slant height of 15 cm, and is removed from the top of the larger cone, as shown in the diagram.

Calculate the radius of the base of the cone which has been removed.

Markscheme / solution

* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure.

$\sqrt {{{15}^2} - {{12}^2}}$ (M1)

Note: Award (M1) for correct substitution into Pythagoras theorem.

$\frac{{{\text{radius}}}}{{21}} = \frac{{15}}{{35}}$ (M1)

Note: Award (M1) for a correct equation.

= 9 (cm) (A1) (C2)

[2 marks]

Examiners’ report

[N/A]