## nerdyotter one year ago The diameter of the base of a right cone is 6 cm. If the total surface area of the cone is 90π cm^2, what is the length of the slant height? a.) 6.6 cm. b.) 9 cm. c.) 21 cm. d.) 27 cm. Could I have the formula to solve this problem?

1. mathstudent55

You need the formula for the total area of a cone. Here it is: $$\Large SA_{cone} = \pi r^2 + \pi r s$$

2. anonymous

SA = (Area of Base) + (Area of cone)

3. mathstudent55

Where r = radius s = slant height

4. anonymous

I just repeated what mathstudent said.

5. anonymous

:/

6. mathstudent55

From the diameter, you can find the radius. You have the total surface area, so the only unknown in the formula is s, the slant height. You can solve for it.