Question

the slant height of the cone is 20 cm and the radius is 10 cm. find the central angle and the radius of the sector used to make this cone ​

Answer 1

Answer:

Side of the square = 5 cm

Base of the isosceles triangle = 5 cm

Height of the isosceles triangle = 8 cm

Area of the square = (side)2 = (5 cm)2 = 25 cm2

Area of one isosceles triangle =  

Area of four isosceles triangles = 20 × 4 cm2 = 80 cm2

Area of the square pyramid = Area of the square + Area of four isosceles triangles

= (25 + 80) cm2  

= 105 cm2

Thus, we need 105 cm2 paper for the job.

Step-by-step explanation:

Answer 2

Step-by-step explanation:

Side of the square = 5 cm

Base of the isosceles triangle 5 cm

Height of the isosceles triangle 8 cm

Area of the square = (side)2 = (5 cm)2 = 25 cm2

Area of one isosceles triangle =Area of four isosceles triangles = 20 x 4 = cm2 = 80 cm2

Area of the square pyramid = Area of the square + Area of four isosceles triangles

= (25 + 80) cm2

= 105 cm2

Thus, we need 105 cm2 paper for the job.