Finding Radius and Diameter from Surface Area of a Sphere

This video tutorial explains how to find the radius of a sphere when given its surface area. The instructor begins by introducing the problem and then guides viewers through the process of using the surface area formula to isolate and solve for the radius. The tutorial also covers how to calculate the diameter once the radius is known. The video concludes with a summary of the steps involved in solving such problems.

What is the main focus of this video?

• Finding the circumference of a circle

• Finding the area of a rectangle

• Finding the radius from the surface area of a sphere

• Finding the volume of a sphere

What is the given surface area in the problem?

• 634 cm²

• 6.34 cm²

• 63.4 cm²

• 63.4 cm

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

• 2πr²

• 4πr

• 4πr²

• πr²

What operation is used to isolate r² in the equation?

• Division

• Multiplication

• Subtraction

• Addition

What value do you get when you divide 63.4 by 4π?

• 5.05

• 6.28

• 2.25

• 3.14

What is the next step after finding r²?

• Divide by 2

• Multiply by π

• Take the square root of the result

• Square the result

What is the radius of the sphere when the surface area is 63.4 cm²?

• 4.5 cm

• 2.25 cm

• 3.14 cm

• 1.5 cm

How do you find the diameter from the radius?

• Subtract 2 from the radius

• Divide the radius by 2

• Add 2 to the radius

• Multiply the radius by 2

What is the diameter of the sphere if the radius is 2.25 cm?

• 2.25 cm

• 1.125 cm

• 4.5 cm

• 3.14 cm

What should you do if asked to find the diameter on a test?

• Write the radius in a sentence

• Double the radius and write it in a sentence

• Divide the radius by 2 and write it in a sentence

• Add 2 to the radius and write it in a sentence