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antiseptic1488 [7]
3 years ago
15

You have a fishing line spool with an end that has an area of 20.0 cm2. How much fishing line do you need to wind around the spo

ol 10 times?
Express your answer (in cm) to three significant figures.
Mathematics
1 answer:
lana66690 [7]3 years ago
3 0
<h3>Problem Solution</h3>

Assuming the spool is a cylinder and the circumference we're winding around is that of a circle with the given area, we can write the relation between circumference and area as

... C = 2√(πA)

10 times the circumference is then

... 10C = 20√(π·20 cm²) = 40√(5π) cm ≈ 159 cm

<h3>Formula Derivation</h3>

The usual formulas for circumference and area are

... C = 2πr

... A = πr²

If we multiply the area formula by π and take the square root, we get

... πA = (πr)²

... √(πA) = πr

Multiplying this by 2 gives circumference.

... C = 2√(πA) = 2πr

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A ship traveling east at 45 mph is 15 mi from a harbor when another ship leaves the harbor traveling east at 60 mph. How long do
Harman [31]

Answer:

  1 hour

Step-by-step explanation:

I find these easiest to work by considering the initial difference in distance and the speed at with that gap is closing.

__

The gap is 15 miles, the distance the first ship is from harbor when the second ship starts.

The rate of closure is the difference in the speeds of the two ships:

  60 mph -45 mph = 15 mph

Then the closure time is ...

  time = distance/speed

  time = (15 mi)/(15 mi/h) = 1 h

It will take the second ship 1 hour to catch up to the first ship.

7 0
2 years ago
Please help with this geometry math problem!
valina [46]

Answer:

∠8 * 4 = ∠7 ----------------(1)

∠8 + ∠7 = 180 ------------(2)

Taking the value of ∠7 from (1) and using it in (2):

<u><em>∠7 = 4 * ∠8</em></u>

<u><em /></u>

∠8 + ∠7 = 180

∠8 + (4 * ∠8) = 180

∠8 + 4∠8 = 180

5∠8 = 180

∠8 = 36° ---------------(3)

Using the value of ∠8 from (3) in (2):

∠8 + ∠7 = 180

36 + ∠7 = 180

∠7 = 144°       and       ∠8 = 36°

4 0
3 years ago
Can you help with #6
ludmilkaskok [199]
If i simplify number 6 it would be -55/63
5 0
3 years ago
a small silver dollar pancake served at the restaurant has a circumference of 2*pi inches. A regular pancake has a circumference
Ludmilka [50]
Pi = 3.14

2*3.14 = 6.28
4*3.14 = 12.56

area = pi [ C/ (2pi)] ^2
C= circumference

area of small = 3.14 (6.28/6.28)^2 =3.14
area of regular = 3.14 (12.56/6.28)^2 = 12.56

12.56/3.14 = 4 

The regular pancake is 4 times the area.



4 0
2 years ago
Can someone help me with this?
shutvik [7]
The answer would be the first one
5 0
3 years ago
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