Answer:
200π
Step-by-step explanation:
Surface area of a cone = πr(r+l)
r is the radius
l is the slant height
Volume of the cone = 1/3πr²h
320π = 1/3πr²h
320 = 1/3r²(15)
320 = 5r²
r² = 320/5
r² = 64
r = 8
l² = 15² + 8²
l² = 225 + 64
l² = 289
l = 17
Get the surface area;
S = πr(r+l)
S = π8(8+17)
S = π*8*25
S = 200π
Hence the surface area of the cone is 200π
X>17
add 7 to 10 and you get 17 :)
How many grey slices are there
I don’t know I’m just doing this for the points I’m sorry ☮️✌️
Answer:11
Step-by-step explanation:
Boys : girls=7:1
Sum of ratio=7+1=8
Let number of girls be y
Then number of boys=y+66
Total number of pupils=y+y+66
Total number of pupils=2y+66
girls only=(girl ratio)/(sum of ratio) x (total number of pupils)
y=1/8 x (2y+66)
Cross multiply
y x 8=2y + 66
8y=2y + 66
Collect like terms
8y-2y=66
6y=66
Divide both sides by 6
6y/6=66/6
y=11
There are 11 girls
