Help me solve this please

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  shaded/square = (50π cm²)/(400 cm²) = π/8

Step-by-step explanation:

The quarter circle has area ...

  A = (1/4)(πr²) = π/4(20 cm)² = 100π cm²

The half-circle has area ...

  A = (1/2)(πr²) = π/2(10 cm)² = 50π cm²

Then the area of the shaded portion is ...

  shaded = 100π cm² -50π cm² = 50π cm²

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The area of the square is ...

  A = s² = (20 cm)² = 400 cm²

Then the ratio of interest is ...

  shaded/square = (50π cm²)/(400 cm²) = π/8

answer: b i think

step-by-step explanation:

no not all of them.

step-by-step explanation:

some of them have a square base.