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39.28 cm²

Step-by-step explanation:

The area (A) of a circle is calculated as

A = πr² ( r is the radius )

Thus the area of a semicircle is one half the area of the circle

A = πr²

The diameter of the circle is 10 cm, thus radius = 0.5 × 10 = 5 cm

A = 0.5 × 3.142 × 5² = 0.5 × 3.142 × 25 ≈ 39.28 cm² ( to 2 dec. places )

answer: 1722

step-by-step explanation:

given: the mass of saturn=

the mass of mercury=

the number of times the mass of saturn is greater than the mass of mercury

hence, the mass of saturn is 1722 times greater than the mass of mercury.