Advertisement Remove all ads

The Slant Height of the Frustum of a Cone is 4 Cm and the Perimeters (I.E. Circumferences) of Its Circular Ends Are 18 Cm and 6 Cm. Find the Curved Surface Area of the Frustum. - Mathematics

Sum

The slant height of the frustum of a cone is 4 cm and the perimeters (i.e. circumferences) of its circular ends are 18 cm and 6 cm. Find the curved surface area of the frustum.

Advertisement Remove all ads

Solution

Let R and r be the radii of the top and base of the frustum of the cone, respectively, and its slant height be l.

Then,

2πR = 18 ⇒ πR = 9   .....(i)

2πR = 6 ⇒ πr = 3     .....(ii)

Curved surface area of the frustum =πl (R + r)

= l × (πR + πr )

= 4 × (9 + 3)   [Since l = 4 cm]  (From (i) and (ii))

= 48 cm2

  Is there an error in this question or solution?
Advertisement Remove all ads

APPEARS IN

RS Aggarwal Secondary School Class 10 Maths
Chapter 19 Volume and Surface Area of Solids
Formative Assessment | Q 15 | Page 938
Advertisement Remove all ads
Advertisement Remove all ads
Share
Notifications

View all notifications


      Forgot password?
View in app×