LEARN · EXPLAIN · REVISE

A cone has radius r and height h. Write its volume as cπ and find c.

Read the idea, work independently, then explain what changed.

TOPIC 01

Introduction to solid geometry: mixed assessment

A mixed assessment: identify the method, justify it and revise your reasoning.

Use one hint at a time. A correction explains what changed, not just the final answer.

01 / Transfer#Your turn

r=9,\quad h=3

Skills and prerequisite lessons

Working and explanation

BUILD THE REASONING

Hint 1

Choose the correct surface or volume formula and keep units and similarity powers consistent.

Hint 2

A cone occupies one third of the corresponding cylinder volume.

Worked solution

Choose the correct surface or volume formula and keep units and similarity powers consistent.
Calculate or simplify this relation.
$V=\frac13\pi r^2h=81\pi$
Do not omit the factor one third.

The requested value is 81.

Checks and common pitfalls: Do not omit the factor one third.

Think first. Reveal a hint when the class is ready.

Teacher preparation and assessment