What multiplies to 24 and adds to 20

Find the area of an octagon whose perimeter is 120 cm.

stira [4]

Answer:

The area of an octagon whose perimeter is 120 cm is 1086.4 $cm^{2}$

Step-by-step explanation:

An octagon is a polygon with eight sides. If the lengths of all the sides and the measurement of all the angles are equal, the octagon is called a regular octagon.

There is a predefined set of formulas for the calculation of perimeter, and area of a regular octagon.

The perimeter of an Octagon is given by

$P=8a$

and the area of an Octagon is given by

$A=2a^{2}(1+\sqrt{2})$

We know that the perimeter is 120 cm, solving for side length (a) in the perimeter formula we get

$120=8a\\\frac{8a}{8}=\frac{120}{8}\\a=15$

Now, we calculate the area

$A=2a^{2}(1+\sqrt{2})\\A=2(15)^{2}(1+\sqrt{2})\\A=450\left(1+\sqrt{2}\right)\\A\approx 1086.4 \:cm^{2}$

5 0

3 years ago

How to set up this problem

HACTEHA [7]

Answer:

The son is five years old

Step-by-step explanation:

Let the son's age be x

A man is five as old as his son, 5x

In five years, he would be three times as old as his son

In five years: son would be x+5

Father 5x+5

3(x+5)=5x+5

3x+15=5x+5

Collect like terms

15-5=5x-3x

10=2x

Divide by 2

10/2=2x/2

x=5

The son is five years old

5 0

3 years ago

Factor completely:<br>64 - y^3

madam [21]

From your equation, you can see that you have a difference of two cubes (aka two cubes being subtracted): 64, which is $4^{3}$ , and $y^{3}$ .

There is rule for the difference of two cubes:
The difference of two cubes is equal to the difference of the cube roots times a binomial, which is the sum of the squares of the roots plus the product of the roots.

That sounds pretty confusing, but it's much easier to understand when put mathematically. Let's say our two cubes are $a^{3}$ and $b^{3}$ . The difference of those two cubes is:
$a^{3} - b^{3} = (a - b)( a^{2} + ab + b^{2})$

In our problem, a = 4 (since $a^{3}$ = 64) and b = y (since $b^{3} = y^{3}$ . Plug these values into the rule to find the factor of $64 - y^3$ :
$64 - y^3 \\
= (4 - y)( 4^{2} + 4y + y^{2}) \\
= (4 - y)( 16 + 4y + y^{2})$

-----

Answer: $(4 - y)( 16 + 4y + y^{2})$

8 0

3 years ago

BRAINIEST ANSWER <br> FIND THE VOLUME AND ROUND TO THE NEAREST TENTH :))) <br> Please help

kolezko [41]

Answer: 3,150 ft.

Step-by-step explanation: multiply all sides together

3 0

3 years ago

Oliver has 3 times as many rocks in his collection as Katie. Then Oliver collected 75 more rocks and Katie collected 105 more ro

Evgesh-ka [11]

Answer:

The answer to your question is Katie had 15 rocks and Oliver 45 rocks.

Step-by-step explanation:

Conditions

Katie has x amount of rocks

Oliver has 3x amount of rocks

The final amount of rocks

Oliver = 3x + 75

Katie = x + 105

Now, they have the same amount of rocks, then we can equal both equations

3x + 75 = x + 105

Solve for x

3x - x = 105 - 75

2x = 30

x = 30/2

x = 15

Conclusions

At first Katie had 15 rocks and Oliver had 3(15) = 45 rocks

5 0

3 years ago

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