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fiasKO [112]
3 years ago
8

What is the area of a circle with a radius of 21 cm?

Mathematics
2 answers:
Lina20 [59]3 years ago
3 0

Answer:

1384.74cm squared

Step-by-step explanation:

A= πr²

Igoryamba3 years ago
3 0
Last one 1384.74 jajajajajajaja
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Please help! Area of part of a circle!!!
Helga [31]

The sector (shaded segment + triangle) makes up 1/3 of the circle (which is evident from the fact that the labeled arc measures 120° and a full circle measures 360°). The circle has radius 96 cm, so its total area is π (96 cm)² = 9216π cm². The area of the sector is then 1/3 • 9216π cm² = 3072π cm².

The triangle is isosceles since two of its legs coincide with the radius of the circle, and the angle between these sides measures 120°, same as the arc it subtends. If b is the length of the third side in the triangle, then by the law of cosines

b² = 2 • (96 cm)² - 2 (96 cm)² cos(120°)   ⇒   b = 96√3 cm

Call b the base of this triangle.

The vertex angle is 120°, so the other two angles have measure θ such that

120° + 2θ = 180°

since the interior angles of any triangle sum to 180°. Solve for θ :

2θ = 60°

θ = 30°

Draw an altitude for the triangle that connects the vertex to the base. This cuts the triangle into two smaller right triangles. Let h be the height of all these triangles. Using some trig, we find

tan(30°) = h / (b/2)   ⇒   h = 48 cm

Then the area of the triangle is

1/2 bh = 1/2 • (96√3 cm) • (48 cm) = 2304√3 cm²

and the area of the shaded segment is the difference between the area of the sector and the area of the triangle:

3072π cm² - 2304√3 cm² ≈ 5660.3 cm²

7 0
2 years ago
What is the center of the circle shown below
ivanzaharov [21]

J

That's the only point within the circle, and it seems like the center. In these questions, just assuming it's perfectly in the center typically works.

7 0
3 years ago
Read 2 more answers
You are standing on a small fire tower 50 feet from a tree. You notice a squirrel in the tree. You measure the angle of depressi
irina [24]

Answer:

44.81 feet

Step-by-step explanation:

see the attached figure to better understand the problem

step 1

In the right triangle ACD

Find the length side AC (height of the small fire tower)

tan(52^o)=\frac{AC}{50} ---> by TOA (opposite side divided by the adjacent side)

Solve for AC

AC=tan(52^o){50}

AC=64\ ft

step 2

In the right triangle ABE

Find the length side AB

tan(21^o)=\frac{AB}{50} ---> by TOA (opposite side divided by the adjacent side)

solve for AB

AB=tan(21^o){50}

AB=19.19\ ft

step 3

How many feet off the ground is the squirrel?

Subtract the length side segment AB from the length side segment AC

so

64-19.19=44.81\ ft

5 0
3 years ago
What is 5x10=50+60=<br> have a nice day
Vanyuwa [196]

Answer:

The answer is One hundred and ten

6 0
2 years ago
I need help on 18,19 and 20 please help do tomorrow
Verdich [7]
You still need help?

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3 years ago
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