Practice variation 2 of 3
Rates of change — A growing circle
Your question
A circle’s radius grows at cm/s. Find when cm.
This practice question was inspired by Question 12(a) in the 2025 NSW HSC Mathematics Extension 1 examination, © NESA. It is an original TestMum variation that practises the same mathematical idea, not an official NESA question.
Before you check
- Have you stated every choice or assumption?
- Can another student follow each line?
- Did you verify the final result independently?