Answer:
25:16 is the surface area of the cones.
Explanation:
Given: The ratio of their radii and altitudes is 5:4.
Area of similar figures are proportional to the squares of their corresponding sides and this ratio is called scale factor.
Let z be the scale factor
∴z=

Now, let x be the surface area of the larger cone
and let y be the surface are of smaller cone.
∴

next substituting the value of z ,
⇒

∴

The ratio for the surface area of cones is 25:16