Whats the surface area of a cone with a height of "50" and a diameter of "40"

56844.9 units squared

Step-by-step explanation:

The surface area of a cone is denoted by: , where r is the radius and l is the slant height. The slant height is basically the length from a point on the base circle to the top vertex of the cone.

Here, since our diameter is 50 and diameter is twice the radius, then our radius is r = 50/2 = 25.

To find the slant height, we have to use the Pythagorean Theorem:

, where h is the height

Now, plug these values of r and l into the first equation above:

≈ 56844.9 units squared

4637.883499 units²

Step-by-step explanation:

Radius 'r'

40/2 = 20

Slant height 's'

sqrt(20²+50²) = 10sqrt(29)

Surface area:

(pi × r × s) + (pi × r²)

[3.14×20×10sqrt(29)] + (3.14×20²)

4637.883499 units²

it is a. 4.2 because 7.6-3.4 gets the remaining length of 4.2. i might be wrong but i am pretty sure this is the answer.