First thing you would have to do is find the area of the entire box, which would be 56 square inches.
Next find the area of all the filled donuts. To find the area of each filled donut you would have to find he radius. Since 3 filled donuts take up exactly 9 inches total, that means each donut is 3 inches long when you divide 9 by 3. 3 inches would be the diameter so the radius would be 1.5 since half the diameter is the radius. Using the formula for a circle's area,
we can plug in each value and we'd get 7.07 square inches for each filled donut. Since there are 3 filled donuts, multiply 7.07 by 3, which would be 21.21 square inches.
21.21 square inches would be the answer to PART 1 question.
Next step would be to find the area taken up by the donuts with holes. We know that if the donuts didn't have holes, then it would be the same size of the filled donut. So that means that all we have to do is find the area of the hole. Since the hole's diameter is 1 inch, the radius is 0.5. Using the same formula for a circle's area, the area of the hole is 0.79 square inches. Taking the filled donut area of 7.07 square inches, we'd subtract that by 0.79 square inch size of the hole to get 6.28 square inches for each donut with a hole. Multiply this by 3 because there are 3 donuts with holes and you would get 18.84 square inches.
Finally, add the amount the space that the 3 filled donuts are taking up, which is 21.21 square inches, with the amount of space that the donuts with holes are taking, which is 18.84 square inches and you would get 40.05 square inches. This is the area that all the donuts are taking up. In order to find the space that donuts are NOT taking up, you would subtract the entire box size of 56 square inches by amount of space that the donuts are taking up of 40.05 square inches. The space NOT taken up by all the donuts would be 15.95 square inches.
The answer to question 7 is 15.95 square inches