Cone Surface Area 6F1084
1. **State the problem:** Find the total surface area of a cone with radius $r=3.78$ m and height $h=2.15$ m.
2. **Formula:** The total surface area $A$ of a cone is given by:
$$A = \pi r^2 + \pi r l$$
where $l$ is the slant height.
3. **Find the slant height $l$:** Use the Pythagorean theorem:
$$l = \sqrt{r^2 + h^2} = \sqrt{3.78^2 + 2.15^2}$$
Calculate inside the root:
$$3.78^2 = 14.2884, \quad 2.15^2 = 4.6225$$
So,
$$l = \sqrt{14.2884 + 4.6225} = \sqrt{18.9109} \approx 4.35$$
4. **Calculate the surface area:**
$$A = 3.14 \times 3.78^2 + 3.14 \times 3.78 \times 4.35$$
Calculate each term:
$$3.78^2 = 14.2884$$
$$3.14 \times 14.2884 = 44.87$$
$$3.14 \times 3.78 \times 4.35 = 51.63$$
5. **Add the two parts:**
$$A = 44.87 + 51.63 = 96.50$$
6. **Final answer:** The total surface area of the cone is **96.50 square meters**.