Answer :
a) The area of Helen's circular garden is 314 m².
b) The estimation for the number of boxes of grass seed Helen needs, is 5 boxes.
c) B. The estimation we did in (b) is an underestimation.
How to find the area of a circle?
The area of a circle is calculated by the formula,
A = πr² sq. units; r - radius
When we have the diameter, we can find the radius by
r = d/2 units
Calculation:
Given that Helen has a garden in the shape of a circle of diameter 20 m.
She is going to cover the garden with grass seed to make a lawn.
Grass seed is sold in boxes. Each box of grass seed will cover 58 m² of the garden.
a) The area of the circular garden is
A = πr² = 3.14 × (d/2)²
⇒ A = 3.14 × (20/2)²
⇒ A = 3.14 × 100
∴ A = 314 m²
Thus, the area of Helen's garden is 314 m².
b) The number of boxes of grass seed to cover the area of 314 m² is
= area of the garden/area covered by each box of seeds
= 314 m²/58 m²
= 5.4179
So, on an estimation, there are 5 boxes of grass seed that Helen needs.
c) Here, in the above estimation, we rounded the decimal number 5.4179 to 5. Since the number is rounded to the nearest value (smallest value), the estimation is an underestimate.
Learn more about the area of a circle at the following link:
https://brainly.com/question/12269818
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