Answer:
Volume of the cone is 1883.7 cm³
Step-by-step explanation:
The circumference of the full circle with radius 18 cm :
360 := 2*π*18 = 36π cm
125 := 125/360 * 36π
The new circumference is maller:
36π - 125/360 * 36π
36π * 0.652(7)
Calculate the new r based on the new circomference:
2*π * r = 36π * 0.652(7)
r = 36π/2π * 0.652(7)
r = 18 * 0.652(7)
r = 11.75 cm
Based on this radius you can calculate the area of the base of the cone.
area base = π*(11.75)²
The Volume V of this cone = 1/3 π r² * h
You can calculate the height h by using Pythagoras theorum.
The sector is the hypothenusa= 18 cm
The h is the height, which is the "unknown"
The r is the new radius = 11.75 cm
s² = r² + h²
h² = s² - r²
h = √(s² - r²)
h = √(18² - 11.75²)
h = 13.6358901432946 cm
h = 13.636 cm
V cone
V = 1/3 π 11.75² * h
V = 1/3 π 11.75² * √(18² - 11.75²)
V = 1/3 π 11.75² * 13.636
V = 1883.7 cm³
