Acone has a diameter of 7 cm and a slant height of 15.5 cm. what is the surface area of the cone?

apply this formula: sa = πr2 + πrl

1. find the radius of the measure: r =
d
2
=
7
2
= 3.5 cm

2. substitute measures into the formula: sa = π(3.52) + π(3.5)(15.5)

3. simplify the power and multiply: sa = 12.25π + 54.25π

4. add to simplify: sa =
π cm2

Total surface area of the cone = 208.81 sq cm

Step-by-step explanation:

Diameter of the cone (d)  = 7 cm

Slant height (L) = 15.5 cm

1) The radius of the cone= Half of the diameter

= 7/2 cm = 3.5 cm

⇒ r = 3.5 cm

Now, Total surface area of the cone =

taking π = 3.14

We get

and  πrl = 3.14 x 3.5 + 15.5 = 170.345

So, Total surface area of the cone  = 38.465 + 170.345 = 208.81 sq cm

i think the correct option is the second option.