Question

please help 3rd question

Answer 1

Hello Mate!

So, for finding total surface area of this toy we need to find surface area of cone and hemisphere.

In hemisphere, radius and height are equal. Since radius of hemisphere is 3.5 cm so height of cone is,

= 15.5 cm - 3.5 cm = 12 cm

Curved surface area of cone = πrl

But we dont have l.

Hence l = √( r² + h² )

= √( 3.5² + 12² )

= √( 12.25 + 144 )

= √156.25 = 12.5 cm

Hence πrl = 22 / 7 × 3.5 × 12.5

= 137.5 cm²

Curved surface area of hemisphere = 2πr²

= 2 × 22 / 7 × 3.5²

= 77 cm²

Total surface area = 137.5 + 77 cm²

= 214.5 cm²

Hence total surface area if toy is 214.5 cm².

Have great future ahead!