Samacheer Kalvi 10th Maths Solutions Chapter 7 Mensuration Ex 7.1

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Tamilnadu Samacheer Kalvi 10th Maths Solutions Chapter 7 Mensuration Ex 7.1

10th Maths Exercise 7.1 Samacheer Kalvi Question 1.
The radius and height of a cylinder are in the ratio 5:7 and its curved surface area is 5500 sq.cm. Find its radius and height.
Solution:
r = 5x
h = 7x
CSA of a cylinder = 2πrh
Samacheer Kalvi 10th Class Maths Mensuration Chapter Solutions
∴ Radius = 5 × 5 = 25 cm
height = 7 × 5 = 35 cm

Ex 7.1 Class 10 Samacheer Question 2.
A solid iron cylinder has total surface area of 1848 sq.m. Its curved surface area is five – sixth of its total surface area. Find the radius and height of the iron cylinder.
The external radius and the length of a hollow
Solution:
10th Maths Mensuration Samacheer Kalvi Ex 7.1 2

10th Maths Mensuration Exercise 7.1 Question 3.
The external radius and the length of a hollow wooden log are 16 cm and 13 cm respectively. If its thickness is 4 cm then find its T.S.A.
Solution:
R = 16 cm
r = R – thickness
r = 12 cm
= 16 – 4 = 12 cm
h = 13 cm
Total surface area of hollow cylinder = 2π(R + r) (R – r + h) sq. units.
Mensuration Class 10 State Board Samacheer Kalvi 10th Maths
∴ T.S.A = 2992 cm2

10th Maths Exercise 7.1 In Tamil Question 4.
A right angled triangle PQR where ∠Q = 90° is rotated about QR and PQ. If QR = 16 cm and PR = 20 cm, compare the curved surface areas of the right circular cones so formed by the triangle.
Solution:
When it is rotated about PQ the C.S.A of the cone formed = πrl.
10th Maths Ex 7.1 Samacheer Kalvi Chapter 7 Mensuration
10th Math 7.1 Solution Samacheer Kalvi
1005.71 > 754.28
∴ CSA of the cone rotated about its PQ is larger than the CSA of the cone rotated about QR.

10th Maths 7.1 Exercise Question 5.
4 persons live in a conical tent whose slant height is 19 cm. If each person require 22 cm2 of the floor area, then find the height of the tent.
Solution:
Base area of the cone = πr2 = sq units.
Samacheer Kalvi 10th Maths Mensuration Ex 7.1 6

10th Mensuration Solutions Question 6.
A girl wishes to prepare birthday caps in the form of right circular cones for her birthday party, using a sheet of paper whose area is 5720 cm2, how many caps can be made with radius 5 cm and height 12 cm.
Solution:
10th Class Maths Exercise 7.1 Samacheer Kalvi

10th Maths Exercise 7.1 Question 7.
The ratio of the radii of two right circular cones of same height is 1 : 3. Find the ratio of their curved surface area when the height of each cone is 3 times the radius of the smaller cone.
Solution:
10th Maths Chapter 7 Exercise 7.1 Samacheer Kalvi
Samacheer 10th Class Mensuration Chapter 7 Solutions Ex 7.1 9

Exercise 7.1 Class 10 Samacheer Kalvi Question 8.
The radius of a sphere increases by 25%. Find the percentage increase in its surface area.
Solution:
Surface area of sphere A = 4πr2
New radius = r’ = 1.25r,
[∵ r + 0.25r] (25% = 0.25)
New surface area = A’ = 4π(r’)2
= 4π(1.25 r)2
Samacheer Kalvi 10th Maths Chapter 7 Mensuration Ex 7.1 10
Exercise 7.1 Class 10 Samacheer Kalvi 10th Maths

10th Class Maths Mensuration Chapter Solutions Question 9.
The internal and external diameters of a hollow hemispherical vessel are 20 cm and 28 cm respectively. Find the cost to paint the vessel all over at ₹ 0.14 per cm2.
Solution:
External diameter D = 28 cm
Internal diameter d = 20 cm
Class 10 Maths Ex 7.1 Solutions Samacheer Kalvi

10th Maths 7.1 Question 10.
The frustum shaped outer portion of the table lamp has to be painted including the top part. Find the total cost of painting the lamp if the cost of painting 1 sq.cm is ₹ 2.
10th Class Maths 10th Chapter Mensuration Samacheer Kalvi
Solution:
Here given that R = 12 m
r = 6 m
h = 8 m
Chapter 7 Maths Class 10 Samacheer Kalvi Mensuration Ex 7.1 14
Maths Chapter 7 Class 10 Samacheer Kalvi