A solid cylinder has a radius of 9 cm and a height of 25 cm. What is the ratio of its total surface area to its curved surface area ?

34 : 25

We know that,

Total surface area of cylinder = 2 × π × r × (r + h)  

Curved surface area of cylinder = 2 × π × r × h

Where, r = radius

h = height

According to the question,

= TSA = 2 × π × 9 × (9 + 25)

= TSA = 2 × π × 9 × (9 + 25)

= TSA = 18 × π × 34 = 612π

Now CSA

= CSA = 2 × π × 9 × 25

= CSA = 225 × 2 × π = 450π 

Now TSA : CSA

= TSA : CSA = 612π : 450π

= TSA : CSA = 612 : 450

= TSA : CSA = 34 : 25