Surface Area of Composite Solids

Mr. Kenyan Ola explains how to find the surface area of a composite solid made of a hemisphere and a cylinder. He discusses the concept of surface area, introduces relevant formulas, and explains how to adjust these formulas for composite figures. The video includes step-by-step calculations for the surface areas of both the hemisphere and the cylinder, and concludes with combining these areas to find the total surface area. Key takeaways emphasize the importance of considering covered parts in composite figures.

What is the main objective of the video tutorial?

• To find the volume of a composite solid.

• To find the surface area of a composite solid.

• To find the perimeter of a composite solid.

• To find the weight of a composite solid.

What two shapes make up the composite solid discussed in the video?

• A cylinder and a cube.

• A sphere and a pyramid.

• A cube and a cone.

• A hemisphere and a cylinder.

What is the formula for the surface area of a sphere?

• 2πr²

• 4πr²

• πr²

• 3πr²

How is the formula for the surface area of a hemisphere derived from that of a sphere?

• By doubling the formula for a sphere.

• By adding the formula for a sphere.

• By halving the formula for a sphere.

• By subtracting the formula for a sphere.

Why is one base of the cylinder not included in the surface area calculation?

• Because it is not a circle.

• Because it is covered by the hemisphere.

• Because it is not needed.

• Because it is too small.

What is the radius of the hemisphere used in the calculation?

• 7

• 4

• 5

• 6

What is the formula used to calculate the lateral area of the cylinder?

• πr²

• 2πrh

• πrh

• 4πr²

What is the total surface area of the composite solid in terms of π?

• 100π cm²

• 250π cm²

• 156π cm²

• 200π cm²

What is the decimal approximation of the total surface area of the composite solid?

• 490.08 cm²

• 500.00 cm²

• 450.00 cm²

• 400.00 cm²

What is the key takeaway when dealing with composite figures?

• Ignore the shapes that are not visible.

• Use only the formula for the largest shape.

• Always add the surface areas of individual shapes.

• Consider which parts of the shapes are covered.