To calculate the surface area of a cone, you can use the formula:
\[ \text{Surface Area} = \pi r (r + l) \]
where:
- \( r \) is the radius of the base of the cone,
- \( l \) is the slant height of the cone.
Given:
- \( r = 10 \) inches,
- \( l = 15 \) inches,
- \( \pi \approx 3.14 \).
Now substituting in the values:
\[ \text{Surface Area} = 3.14 \times 10 \times (10 + 15) \] \[ = 3.14 \times 10 \times 25 \] \[ = 3.14 \times 250 \] \[ = 785 \text{ square inches} \]
Thus, the surface area of the cone is 785 square inches.