C=πd where C=circumference, π=the constant pi, and d=diamter
d=C/π and since we are told that C=9π
d=9π/π
d=9
Using the formulas here: http://www.1728.org/diamform.htm
A) Volume = <span>π <span>• r² • height
radius^2 = Volume / (PI*height)
</span></span><span>radius^2 = 12,566.4 / (PI * 8)
</span>radius^2 =
<span>
<span>
<span>
500.0011692175
</span>
</span>
</span>
radius =
<span>
<span>
<span>
22.3607059195
</span>
</span>
</span>
radius (rounded) = 22.4 cm
B) Area of base = PI * radius^2
Area of base = 3.14159265 * 500
Area of base =
<span>
<span>
<span>
1,570.7963267949
</span>
</span></span><span><span>Area of base (rounded) =
</span>
1,570.8 square cm
</span>
C) <span><span>lateral area = </span>2 • </span><span>π • r • height </span>
<span>lateral area = 2 • </span><span>π • 22.4 * 8
</span>lateral area =
<span>
<span>
<span>
1,125.9468070466
</span>
</span>
</span>
lateral area =
1,125.9 <span>square cm
D) Total Surface Area = </span><span>(2 • <span>π <span>• r²) + (2 • <span>π • r • height)</span></span></span></span>
Total Surface Area = <span><span>2 * (top AND bottom area which is the Part B answer times 2) + (the lateral area which is the Part C answer)
</span>
Total Surface Area = </span>( 2 * 1,570.8 ) + (1,125.9)
<span>Total Surface Area = 3,141.6 + 1,125.9
</span><span>Total Surface Area = </span>
<span>
<span>
<span>
4,267.5
</span>
</span>
</span>
square cm
Answer:
Step-by-step explanation
Take the square root of both sides.
Add both sides by 5
(a-b) X (a+b)
= aXa - bXa +aXb -bXb (distributing)
Now, cross product of a vector with itself = 0
so, aXa = 0, bXb = 0
Also, aXb = - bXa
so,
(a-b) X (a+b) = 0 + aXb + aXb + 0
= 2aXb
hence, proved :)
