2. Main Idea and New Vocabulary Key Concept: Surface Area of a Pyramid
Example 1: Surface Areas of a Pyramid
Example 2: Real-World Example
Key Concept: Surface Area of a Cone
Example 3: Surface Area of a Cone
Lesson Menu

3. Find the lateral and total surface areas of pyramids and cones.
regular pyramid
slant height
Main Idea/Vocabulary

4. Key Concept

5. Surface Areas of a Pyramid
Find the lateral and total surface areas of the triangular pyramid.
L.A. = Pℓ
S.A. = L.A. + B
S.A. =
S.A. = 70.8
L.A. = • 15 • 8
L.A. = 60
Answer: The lateral and total surface areas are 60 and 70.8 square inches.
Example 1

6. Find the lateral and total surface areas of the triangular pyramid.
A. 20 m2; 26 m2
B. 30 m2; 36 m2
C. 30 m2; 46 m2
D. 60 m2; 66 m2
Example 1 CYP

7. TOYS A toy block has the shape of a regular pyramid with a square base
TOYS A toy block has the shape of a regular pyramid with a square base. The manufacturer wants to paint the lateral surface green. How many square centimeters will be painted green?
Example 2

8. L.A. = Pℓ Lateral surface area of a pyramid
L.A. = • 28 • 8 P = 7(4) or 28 and ℓ = 8
L.A. = 112 Simplify.
Answer: So, 112 square centimeters of the toy will be painted green.
Example 2

9. ORNAMENTS A garden ornament is a square pyramid with an 11-inch-long base and a 24-inch slant height. Find the ornament’s lateral surface area.
A. 352 in2
B. 528 in2
C. 649 in2
D. 1,056 in2
Example 2 CYP

10. Key Concept 3

11. L.A. = rℓ Lateral area of a cone
Surface Area of a Cone
Find the lateral and total surface areas of the cone. Round to the nearest tenth.
L.A. = rℓ Lateral area of a cone
L.A. =  • 6 • 13.4 Replace r with 6 and ℓ with 13.4.
L.A.  Simplify.
S.A. = L.A. + r2 Surface area of a cone
S.A. =  • 62 Replace L.A. with and r with 6.
S.A.  Simplify.
Example 3

12. Surface Area of a Cone
Answer: The lateral and total surface areas of the cone are about and square meters.
Example 3

13. Find the lateral and total surface areas of the cone
Find the lateral and total surface areas of the cone. Round to the nearest tenth.
A cm2; cm2
B cm2; cm2
C cm2; cm2
D cm2; cm2
Example 3 CYP