Total surface area of a cone

Question 1

Net of a Cone

Answer 1

Question 2

What is the curved surface area of a cone with slant height l and base radius h?

Answer 2

Curved surface area = Area of rectangle

= πr * l

= πrl

Question 3

What is the Total surface area of a cone?

Answer 3

Total Surface Area

= Curved surface plus area of circle

= πrl + πr²

= πr(l + r)

Question 4

Find the curved surface area of the cone correct to 3 significant figures (Take π = 3.142)

Answer 4

Curved Surface Area

= 3.142 * 3 * 12

= 113.113 cm²

= 113 cm²

Question 5

Find the total surface area of the cone correct to 3 significant figures (Take π = 3.142)

Answer 5

Total Surface Area

= 3.142 * 3 * 12 + 3.142 * 3²

= 141.39 cm²

= 141 cm²

Question 6

Find the curved surface area of the cone correct to 3 significant figures (Take π = 3.142)

Answer 6

radius = 17 / 2

8.5 cm

Curved Surface Area

= 3.142 * 8.5 * 20

= 534.148 cm²

= 534 cm²

Question 7

Find thetotal surface area of the cone correct to 3 significant figures (Take π = 3.142)

Answer 7

radius = 17 / 2

8.5 cm

Total Surface Area

= 3.142 * 8.5 * (20 + 8.5)

= 761.1495 cm²

= 761 cm²