A right prism is based on a triangular base whose perimeter is 26 cm and radius of the in circle of the triangular base is 5 cm. If the volume of the prism is 780 cm3, then find the height of the prism.
A right prism is based on a triangular base whose perimeter is 26 cm and radius of the in circle of the triangular base is 5 cm. If the volume of the prism is 780 cm3, then find the height of the prism. Correct Answer 12 cm
Since the perimeter of the triangular base is 26 cm.
⇒ Semi-perimeter, s = 26/2 = 13 and inradius (r) = 5 cm
inradius of a triangle = A/s
⇒ Area (A) = 13 × 5 = 65 cm2
Volume of prism = (Area of base) × Height
⇒ 780 = 65 × Height
⇒ Height = 780/65 = 12
∴ Height of the prism = 12 cm
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Feb 20, 2025