Work out the following question in your journal and upload your work for your instructor. Be sure your answers are labeled clearly and your steps are shown so that your instructor can see how you arrived at your answer and can give you help if you make an error.

The diameter of a waffle cone is 3.5 inches, and its height is 8 inches.

a. Assuming there is no overlap, how much waffle does it take to make the cone? Round your answer to the nearest square inch.

- 2 points for the correct answer
- -1 point for a rounding error or units error
- 2 points for showing your work clearly

b. If this cone is packed full with ice cream and filled just to the brim, how many cubic inches of ice cream will it hold? Round your answer to the nearest cubic inch. Include all work and any formulas used in your answer.

- 2 points for the correct answer
- -1 point for a rounding error or units error
- 2 points for showing your work clearly

c. How many perfectly spherical scoops of ice cream could melt into this cone without overflowing? Assume the diameter of the spherical scoops is the same as the diameter of the cone (3.5 inches). Include all work and any formulas used in your answer.

- 2.5 points for the correct answer
- -1 point for a rounding error or units error
- 2 points for showing your work clearly



Answer :

Sure, let's break down each part of the question and work through the steps.

### Given:
- Diameter of the cone = 3.5 inches
- Height of the cone = 8 inches

### Solution:

#### Part a: Surface area of the cone (excluding the base)

To find the surface area of a cone (excluding the base), we need to use the formula for the lateral surface area:
[tex]\[ \text{Lateral Surface Area} = \pi \times r \times l \][/tex]
where [tex]\( r \)[/tex] is the radius of the cone and [tex]\( l \)[/tex] is the slant height.

1. Calculate the radius:
[tex]\[ r = \frac{\text{diameter}}{2} = \frac{3.5}{2} = 1.75 \text{ inches} \][/tex]

2. Calculate the slant height [tex]\( l \)[/tex]:
[tex]\[ l = \sqrt{r^2 + h^2} = \sqrt{1.75^2 + 8^2} = \sqrt{3.0625 + 64} = \sqrt{67.0625} = 8.19 \text{ inches} \][/tex]

3. Calculate the lateral surface area:
[tex]\[ \text{Lateral Surface Area} = \pi \times 1.75 \times 8.19 = 45.02 \text{ square inches} \][/tex]

4. Round to the nearest square inch:
[tex]\[ \text{Rounded Surface Area} = 45 \text{ square inches} \][/tex]

So, the waffle cone takes approximately [tex]\( 45 \)[/tex] square inches of waffle material to make.

#### Part b: Volume of the cone

To find the volume of a cone, we use the formula:
[tex]\[ \text{Volume} = \frac{1}{3} \pi r^2 h \][/tex]

1. Calculate the volume:
[tex]\[ \text{Volume} = \frac{1}{3} \pi (1.75)^2 \times 8 = \frac{1}{3} \pi \times 3.0625 \times 8 = \frac{1}{3} \pi \times 24.5 = 25.66 \text{ cubic inches} \][/tex]

2. Round to the nearest cubic inch:
[tex]\[ \text{Rounded Volume} = 26 \text{ cubic inches} \][/tex]

So, the cone can hold approximately [tex]\( 26 \)[/tex] cubic inches of ice cream.

#### Part c: Number of spherical scoops

Next, we need to find out how many perfectly spherical scoops of ice cream (with diameter 3.5 inches) can fit into the cone.

1. Calculate the volume of a spherical scoop:
[tex]\[ \text{Volume} = \frac{4}{3} \pi r^3 \][/tex]
Since the diameter of the scoop is 3.5 inches, the radius is:
[tex]\[ r = \frac{3.5}{2} = 1.75 \text{ inches} \][/tex]
[tex]\[ \text{Volume} = \frac{4}{3} \pi (1.75)^3 = \frac{4}{3} \pi \times 5.359375 = 22.45 \text{ cubic inches} \][/tex]

2. Calculate the number of scoops:
[tex]\[ \text{Number of scoops} = \frac{\text{Volume of cone}}{\text{Volume of one scoop}} = \frac{25.66}{22.45} = 1.14 \][/tex]

3. Round to the nearest whole number:
[tex]\[ \text{Rounded Number of Scoops} = 1 \][/tex]

So, approximately 1 spherical scoop of ice cream could melt into the cone without overflowing.

### Summary of Answers:
a. [tex]\( 45 \)[/tex] square inches
b. [tex]\( 26 \)[/tex] cubic inches
c. [tex]\( 1 \)[/tex] spherical scoop