- The side of a square based prism is 2.5 cm and its height is 6.5 cm . Find its lateral and total surface area.
Solution:
a = 6.5 c
h = 6.5cm
LSA = Ph = Psquare x h
4ah = 4 x 2.5 x 6.5
= 65 cm2
TSA = 2B + Ph = 2a2 + Ph = 2(2.5)2 + 65 = 77.5cm2
- The perimeter of a regular triangle based prism is 18 m and its height is 13 m. find its LSA and TSA.
Solution:
Regular triangular based prsim(equilateral triangle)
P Δ = 18m
h = 13m
LSA ? and TSA=?
LSA = Ph = 18 x 13 = 234m2
We have B = area of base
A = P/3 = 18/3 = 6cm
Then, B = √3 x 6 x 6/2 = 18√3
TSA = 2B + Ph = 2×18√3 + 234 = (36√3 + 234)m2
- The shaper of a pole is in the form of square based prism. If its side is 2 feet and latest surface area is 160 square feet. Find the height of the pole
Solution:
LSA = 160 sq. ft.
a = 2ft
h= ?
LSA = Ph (since P = 4a)
160 = 4ah = 4 x 2 x h
h = 160/8 = 20 ft.
- The TSA of a triangular based prism is 570 cm2 and its height is 22 cm. if the area of its base is 24 cm2 . Find the perimeter of the base.
Solution:
TSA = 576 cm2
h = 22 cm.
B = 24 cm2
P = ?
TSA = 2B + Ph
576 = 2×24 + Px22
576 = 48 + 22P
22P = 576 -48 = 528
P = 528/22
P = 24 cm
1 thought on “Mensuration – Exercise 4.6.3 – Class IX”
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