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Sloan [31]
3 years ago
13

Find the area of of a regular octagon with side length 20 cm.

Mathematics
1 answer:
Alla [95]3 years ago
8 0

A=2(1+\sqrt{2})a^2=2·(1+\sqrt{2})·20^2≈1931.37085cm²

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Alexandra [31]

Answer: 24

Step-by-step explanation:

Basically you just need to add the sides up to get your answer, its like breaking it up and adding simply.

3 0
3 years ago
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Hi, I am new to this website :) I'm currently taking an online trig class on De Moivre's theorem and I don't understand it at al
Vladimir [108]
De Moivre's theorem uses this general formula z = r(cos α + i<span> sin α) that is where we can have the form a + bi. If the given is raised to a certain number, then the r is raised to the same number while the angles are being multiplied by that number.

For 1) </span>[3cos(27))+isin(27)]^5 we first apply the concept I mentioned above where it becomes

[3^5cos(27*5))+isin(27*5)] and then after simplifying we get, [243 (cos (135) + isin (135))] 

it is then further simplified to 243 (-1/ √2) + 243i (1/√2) = -243/√2 + 243/<span>√2 i
and that is the answer.

For 2) </span>[2(cos(40))+isin(40)]^6, we apply the same steps in 1)

[2^6(cos(40*6))+isin(40*6)],

[64(cos(240))+isin(240)] = 64 (-1/2) + 64i (-√3 /2)

And the answer is -32 -32 √3 i

Summary:
1) -243/√2 + 243/√2 i
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7 0
3 years ago
Tom's toy box is shown below. The toy box is shaped like a rectangular prism. It has 5 wooden faces and is open on the top. What
mihalych1998 [28]

Answer:

1100 square inches

Step-by-step explanation:

The faces are all rectangles (area = length x width)

Area of bottom:  20 x 10 = 200

Area of front: 20 x 15 = 300

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Area of right side: 10 x 15 = 150

Area of left side (same as right side) = 150

Total of all the sides: 1100

8 0
3 years ago
POLS HELP ME NOWWWW I DONT UNDERSTAND IT
Leni [432]

Answer:

B

Step-by-step explanation:

using the equation 'y = 12x', if you plug in zero for 'x' you get zero for 'y'; the only graph that has the point (0, 0) is (b)

also, the x-axis represents time so, as time increases, so does the number of calories burned (which is measured on the y-axis) -- not staying flat or decreasing

5 0
3 years ago
Find the missing side of triangle
Maksim231197 [3]

<u>Final Answer:</u>

x = 20

<u>Step-by-step explanation:</u>

we'll be using the pythagorean theorem method, in this triangle the missing letter is a.

formula: a=\sqrt{c^2-b^2}

a = x

b = 21

c = 29

a = \sqrt{29^2-21^2}

a = \sqrt{841-441}     (note: 29² = 29 × 29 = 841 and 21² = 21 × 21 = 441)

a = \sqrt{400}

a = 20

x = 20

7 0
3 years ago
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