A circle has radius 1 cm and a second circle has radius 2 cm. By what factor is the area of the second circle larger than the first?
Answer and explanation
Correct answer: B. 4/1
- Step 1: Area is proportional to the radius squared.
- Step 2: Factor = (2/1) squared = 4/1.
Answer
4/1.
Why not the others: 2/1: areas depend on the square of the radius, not the radius itself. 3: the areas were subtracted without dividing. 8/1: the cube of the radius was used.
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