Question

The circular face of a watch has an area that measures between 800 and 900 square millimeters.

What could be the radius of the watch face? Use 3.14 for Pi.

14 mm
15 mm
16 mm
17 mm

Answer 1

16mm

Explanation:

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Answer 2

Answer: Third option.

Explanation:

The area of a circle can be calculated with the following formula:

`A=\pi r^2`

Where "r" is the radius of the circle.

Using
`\pi =3.14`, this is:

`A=3.14r^2`

According to the information given in the exercise, the area of the circular face of the watch measures between 800 and 900 square millimeters. Knowing this, we can check each option:

1) Substitute
`r=14\ mm` into the formula and evaluate. Then:

`A=(3.14)(14\ mm)^2=615.44\ mm^2` (This could not be the radius of the watch face)

2) Substitute
`r=15\ mm` into the formula and evaluate. Then:

`A=(3.14)(15\ mm)^2=706.5\ mm^2` (This could not be the radius of the watch face)

3) Substitute
`r=16\ mm` into the formula and evaluate. Then:

`A=(3.14)(16\ mm)^2=803.84\ mm^2` (This could be the radius of the watch face)

4) Substitute
`r=17\ mm` into the formula and evaluate. Then:

`A=(3.14)(17\ mm)^2=907.46\ mm^2` (This could not be the radius of the watch face)