Answer:
1. Volume of a cone: 1. V = (1/3)πr2h 2. Slant height of a cone: 1. s = √(r2 + h2) 3. Lateral surface area of a cone: 1. L = πrs = πr√(r2 + h2) 4. Base surface area of a cone (a circle): 1. B = πr2 5. Total surface area of a cone: 1. A = L + B = πrs + πr2 = πr(s + r) = πr(r + √(r2 + h2))
Step-by-step explanation:
1. Volume of a cone: 1. V = (1/3)πr2h 2. Slant height of a cone: 1. s = √(r2 + h2) 3. Lateral surface area of a cone: 1. L = πrs = πr√(r2 + h2) 4. Base surface area of a cone (a circle): 1. B = πr2 5. Total surface area of a cone: 1. A = L + B = πrs + πr2 = πr(s + r) = πr(r + √(r2 + h2))
Factor
find wht 2 numbers add to 8 and multiply to 3
none do
use quadratic formula which can be used when
ax^2+bx+c=0
x=

a=1
b=8
c=3
x=

x=

x=

x=

x=

x=

or x=

aprox x=-7.60555 or x=-0.394449
answers
1) 70
2) 3,840
3) 24
4) 72
<u>Explanation</u>
Q1
The surface area of a cone is given by;
S.A = 2Πrl + Πr²
Where r is the radius of the base and l is the lateral height.
Πr² = area of the base = 20 in²
2Πrl = Area of the lateral surface
= 2.5 × 20
= 50
Area of the cone = 50 + 20
= 70 in²
Q2
The sides of the Pythagorean triangle with legs of 12 and 16.
The 3rd side will be;
c = √(12² + 16²)
= √400 = 20
Volume = 12 × 16 × 20
= 3,840
Q3
The volume of a cone is given by;
volume = 1/3 Π r² h
This shows that the volume of a cone is a third the volume of the cylinder.
∴ Volume of the cylinder = 12 × 3
= 24 ft³
Q4
The volume of any regular figure is;
Volume = base area × height
When the dimensions area usually 3. Let these dimensions be x, y and z.
∴ volume = x × y × z = 9
Doubling the dimensions;
Volume = 2x × 2y × 2z = 2 × 2 × 2 × 9
= 8 × xyz = 8 × 9
= 72 ft²
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