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in the given square based pyramid tha ratio of vertical height and lant height is 4:5 and the total surface area is 96cm find the volume of pyramid

User DavSev
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1 Answer

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22 votes

Answer:

Explanation:

A square pyramid's height-to-slant height ratio is expressed as 4:5

Given that the TSA of a square pyramid is 96 cm, let the height be 4x and the slant height be 5x.

TSA = LSA + area of the base (eq1)

LSA = base perimeter x slant height / 2

Here, the ratio is radius = side of base / 2

we have a relation,

l^2 = r^2 + h^2

(5x)^2 = (s/2)^2 + (4x)^2

√[25x^2 - 16x^2 ] = s/2

√9x^2 = s/2

=> s = 6x cm

from eq(1) ,

96 = 4s × 5x /2 + s^2

=> 96 = 60x^2 + 36x^2

=> 96 = 96x^2

=> x = 1cm

Therefore, height is 4(1) = 4cm,

slant height is 5(1) = 5cm,

side is 6cm.

Area of base x Height = Volume of Pyramid

= s^2 × 4/3 = 36 × 4 /3 = 48cm^3

User Giogix
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