Question

The pencil is 17 cm long in the height of the cup is 15 cm. What is the width of the cup?

Answer 1

The given figure is a circular cylinder, and the pencil represents its diagonal.

We know that

• The pencil is 17 cm.

,

• The height is 15 cm.

Notice that the pencil, the height of the cup, and its width form a right rectangle.

We use Pythagorean's Theorem to find the width w. Remember that this theorem relates the square hypotenuse with the sum of the square of the legs.

`(17)^2=(15)^2+w^2`

Let's solve for w

`\begin{gathered} 289-225=w^2 \\ w^2=64 \\ w=\sqrt[]{64} \\ w=8 \end{gathered}`

Therefore, the width is 8 centimeters long.