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3 years ago

How to find the area of a circle with the circumference?

1 answer:

5 0

You can abuse the fact that PI is Circumference/diameter.

This means that, to find the diameter, you would have to do the following:

PI = circumference/diameter
(You can choose the number of decimals of PI, based on how accurate you want the diameter. 3.14 tends to work for most cases.)

After youve done this, you would be able to find the diameter like this:
PI*diameter = circumference
diameter = Circumference/pi

Then, you can use the diameter/2 to find the radius, like this:
radius = diameter/2

After this, you can simply use the formula for the surface area of a circle, like this:

SA = PI*Radius^2

I might be able to add an example, if really needed.

You might be interested in

Find the distance between (4,6) and (-2, -2)

Nataly [62]

Answer:

$\displaystyle d = 10$

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Algebra II

Distance Formula: $\displaystyle d = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

Step-by-step explanation:

Step 1: Define

Point (4, 6)

Point (-2, -2)

Step 2: Find distance d

Simply plug in the 2 coordinates into the distance formula to find distance d

Substitute [DF]: $\displaystyle d = \sqrt{(-2-4)^2+(-2-6)^2}$
Subtract: $\displaystyle d = \sqrt{(-6)^2+(-8)^2}$
Exponents: $\displaystyle d = \sqrt{36+64}$
Add: $\displaystyle d = \sqrt{100}$
Evaluate: $\displaystyle d = 10$

8 0

2 years ago

Read 2 more answers

Sweets are sold loose, or pre-packed in 120g bags. The 120g bags are ?1.49 each. The loose sweets are ?0.89 for 100g. By calcula

tester [92]

Answer:

The loose sweets at ?0.89 for 100 g.

Step-by-step explanation:

First, calculate the price per gram. You do this by dividing the price by the grams.

?1.49 / 120 g = 1.49 / 120 = 0.0124 (4 dp)

Because the answer was very long, I have rounded it to 4 decimal places (4 dp).

?0.89 / 100 g = 0.89 / 100 = 0.0089

Next, you must calculate both pre-packed and loose sweets to the same weight. I am calculating them both to 100 g.

0.0124 x 100 = 1.24

0.0089 x 100 = 0.89

Finally, the cheapest product for 100 g will be the better value. In this case, it is the loose sweets.

6 0

3 years ago

For each circle equation shown below, state the coordinates of its center and the length of its radius. (a) 2 216x y (b)

gavmur [86]

Answer:

(a) center: (0, 0); radius: 4

(b) center: (8, -3); radius: 10

(d) center: (6, 0); radius: 1

(e) center: (0, 0); radius: 5

(f) center: (3, 8); radius: 8

Step-by-step explanation:

In the figure attached, the complete question is shown.

Equation of a circle with center (h, k) and radius r:

(x - h)² + (y - k)² = r²

8 0

3 years ago

An airplane climbs at an angle of 13 with the ground . What is the distance it has traveled when it has attained an altitude of

nevsk [136]

The distance traveled is the hypotenuse of the right triangle formed with the ground.

sinα=400/d

d=400/sinα, we are told α=13° so

d=400/sin13 ft

d≈1778ft (to nearest whole foot)

6 0

3 years ago

What is the solution to the equation 8 - 2b = -2/3(12b + 6)?

Delvig [45]

8 - 2b = -2/3(12b + 6)
8 - 2b = -8b -4
8 + 4 = -8b + 2b
12 = -6b
b = -12/6
b = -2

So, your final answer is b = -2

8 0

3 years ago