Not A because regular means all sides are equal.
B has to be the answer because the others are not.
Not C because a right triangle is not regular, i.e. and equilateral triangle.
Not D because a rectangle has different side lengths.
No.1
r=9
No.3
r=10.5ft
No.5
C=132m
No.7
C=25.12
No.9
44
No.11
264cm
No.13
97.34m
No.15
47.1
No.17
Am not sure
Hope this helps though
Answer:
x = 10 cm, y = 5 cm gives a minimum area of 300 cm^2.
Step-by-step explanation:
V= x^2y = 500
Surface area A = x^2 + 4xy.
From the first equation y = 500/x^2
So substituting for y in the equation for the surface area:
A = x^2 + 4x * 500/x^2
A = x^2 + 2000/x
Finding the derivative:
dA/dx = 2x - 2000x^-2
dA/dx = 2x - 2000/x^2
This = 0 for a minimum/maximum value of A, so
2x - 2000/x^2 = 0
2x^3 - 2000 = 0
x^3 = 2000/ 2 = 1000
x = 10
Second derivative is 2 + 4000/x^3
when x = 10 this is positive so x = 10 gives a minimum value of A.
So y = 500/x^2
= 500/100
= 5.
So you are using Volume...
V=1/3(pi)r^2h
as you go thu this equation
15 x 15 =225
12 x12= 144
225-144= 81
81/9=9
which your piece would be 1/3 pi r^2h answer is 1356.48
and you round it to the nearest tenth. So
( 1356.5) is ur answer...... So (B)
