A pipe has a right prism shape with an equilateral triangle base of side 6 cm and length 40 cm. Find its water-holding capacity.
623.5 cm³
A right prism holds water equal to its volume, and the volume of a prism is the area of its uniform cross-section (the base) multiplied by its length.
The base is an equilateral triangle of side 6 cm, whose area \(= \frac{\sqrt{3}}{4}\times a^2 = \frac{\sqrt{3}}{4}\times 6^2\).
\(= \frac{\sqrt{3}}{4}\times 36 = 9\sqrt{3} \text{ cm}^2\).
Taking \(\sqrt{3}\approx 1.732\), base area \(= 9 \times 1.732 = 15.588 \text{ cm}^2\).
Volume \(= \text{base area}\times \text{length} = 15.588 \times 40 \approx 623.5 \text{ cm}^3\).
Key concept: volume of any right prism \(= \text{cross-sectional area}\times \text{length}\), with the equilateral-triangle area formula \(\frac{\sqrt{3}}{4}a^2\) for the base.
Hence the water-holding capacity of the pipe is 623.5 cm³.
Two identical regular right pyramids, each with a square base of side 6 cm and a perpendicular height of 4 cm, are stacked one on top of the other such that their bases perfectly align. The top pyramid is inverted. Calculate the slant height of a single pyramid.
A right hexagonal prism has a base edge of 5.5 cm and a height of 12 cm. The lateral faces are all painted. If the cost of painting is ₹22.5 per cm², find the total painting cost. Use \(\sqrt{3} \approx 1.732\) where needed.
A sphere of radius 30 cm is melted and recast into hemispherical bowls, each of external radius 10 cm and wall thickness 1 cm. How many such bowls can be made? (in approx)
In designing pistons, two cylinders have equal heights but one has twice the diameter of the other. What is the ratio of their volumes?
A manufacturer reduces the diameter of their spherical bearing balls by 50% to cut costs. What is the percentage decrease in volume of each ball?
The base of a regular right pyramid is an isosceles triangle with equal sides of 25 cm and a base of 30 cm. The slant height of the pyramid is 40 cm. Find the total surface area of the pyramid.
If the surface area of a sphere increases by 44%, by what approximate percent does the radius increase?
A right prism has a trapezoidal base with parallel sides 6 cm and 10 cm, height of trapezoid 4 cm, and prism height 12 cm. Find the volume.
The outer diameter of a hollow cylindrical iron rod is 8.4 cm. The rod is 28 mm thick and is 30 cm long. If the weight of 1 cm3 of iron in the rod is 0.5 kg, then find the total weight of the rod.
In a manufacturing plant, a cone-shaped part has a curved surface area of 330 cm² and a base radius of 7 cm. What is its height?
A cone and a hemisphere have equal bases and volumes. What is the ratio of the height of the cone to the radius of the hemisphere?
A cube is 7 cm of an edge and another cube is 14 cm on an edge. The ratios of their surface areas are
Using three distinct points which of the following shapes cannot be formed?
Two cubes each of edge 12 cm are joined end to end. Find the surface area of the resulting cuboid.
The areas of three adjacent faces of a cuboid are x, y, z. If the volume is V, then V 2will be equal to: