Use the formula for the volume of a cone to find the missing dimension.
r≈ 0.9in
Practice makes perfect
We want to find the missing dimension of the cone. We know that the cone has a height of 4.2 inches and a volume of 3.6 cubic inches. This means that the missing dimension is the radius r. Let's first make a simplified diagram of the ice cream cone.
We will use the formula for the volume of a cone to find the value of r.
V=1/3π r^2 h
Remember that we always need to check that the measurements are given in the same unit before we substitute them into the formula. In our diagram, we can see that both the height and the volume are given in inches. Next, we will substitute 4.2 for h and 3.6 for V into the formula and solve for r.
Notice that the height cannot be negative, therefore we only care about the positive root. The radius and the volume are given in inches. This means that the radius must be in inches as well. The radius of the cone is about 0.9 inches.
