Answer:
Part A:
The surface area of a cylinder is given by
A= 6πr² if h= 2r
Part B:
Total Cost of covering the cylinder = Rate *2πrh + rate*2πr²
Cost of covering only the side = Rate *2πrh
Step-by-step explanation:
Part A:
The surface area of a cylinder is given by
A= 2πrh + 2πr²
Where h= height and radius = r
But we have the height twice as radius so h= 2r
So putting h= 2r we get
A= 2πr(2r) + 2πr²
A= 4πr² + 2πr²= 2πr²(2+1) = 2πr²(3)= 6πr²
Part B:
Cost = Rate * area of the wall + rate * area of the top and bottom
Cost = Rate *2πrh + rate*2πr²
Where area of the top and bottom= πr² +πr² =2 πr²
and area of the side = 2πrh
Multiplying both with the rate and then adding would give the total cost of materials needed to cover the outside of the cylinder and from top and bottom as well.
If you do not need to cover top and bottom then the expression would be
Cost of covering only the side = Rate *2πrh
Part C:
Already done above.
Answer:
2.7 in²
Step-by-step explanation:
similar triangles have the same angles, and all side lengths (or other distances) of one triangle have the same scaling factor to the side lengths of the other triangle.
so, we know the relation between the 2 baselines is 2/3, as this is the factor to turn the baseline of the large triangle into the baseline of the smaller triangle.
in other words
EF = BC × 2/3
2 = 3 × 2/3
correct
how do we calculate the area of a triangle ?
Area = baseline × height / 2
from BAC we know
Area = 6
baseline = 3
height = ?
6 = 3 × height / 2
12 = 3 × height
height = 4
aha !
now, EDF has a height too that we need to calculate is Area. and this height has the same scaling factor compared to the larger triangle as the side lengths : 2/3
so, for EDF we know
Area = ?
baseline = 2
height = 4 × 2/3 = 8/3
therefore, the area is
Area = (2 × 8/3) / 2 = (16/3) / 2 = 8/3 = 2.66666... ≈ 2.7
the shirt answer would be :
we know from the 2 baselines that the scaling factor for each distance is 2/3.
for the area we need to multiply 2 distances, so that means we have to multiply both by 2/3. and so on the formula for the area we have to use 2/3 × 2/3.
2/3 × 2/3 = 4/9
=>
Area small = Area large × 4/9 = 6 × 4/9 = 24/9 = 8/3 ≈ 2.7
Hello,
3(2m-9+6m)=3m+29-7m
==>3(8m-9)=-4m+29
==>24m+4m=29+27
==>28m=56
==>m=2
Answer B
