2. The radius of a circle is 7cms. The angle subtended by an arc of the circle at centre is 45º. Find the area of sector.

Mathematics

1 answer:

Vitek1552 [10]3 years ago

3 0

Answer:

19.2cm²

Step-by-step explanation:

Given parameters:

Radius of the circle = 7cm

Angle subtended by the arc = 45°

Unknown:

Area of the sector = ?

Solution:

To find the area of the sector, use the expression below;

Area of sector = $\frac{Angle of the arc}{360} x \pi r^{2}$

where r is the radius ;

Insert the parameters and solve;

Area of sector = $\frac{45}{360}$ x $\pi$ x 7²

Area of sector = 19.2cm²

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The sum of the interior angles of an n gon is <span> (n-2)*180
the measure of each interior angle is </span><span>(n-2)*180/n
the measure of each individual exterior angle of an ngon is 360/n
all exterior angles add to 360

1. sum of 15 gon is
(15-2)*180=13*180=2340 degrees

2. deca is 10
(10-2)*180/10=8*18=144 degrees

3. dodecagon is 12 sides
360/12=30 degrees

4. 4 sides, those are exterior angles, so they add to 360
4r+7r+8r+5r=360
24r=360
r=15 degrees

5.
pentagon or 5 sides
sum of internal is (5-2)*180=3*180=540 degrees
540=4z+5z+3z+5z+3z
540=20z
27 degrees=z
3z=81=A=D
4z=108=B
5z=135=C=E

6. (n-2)*180
20 gon
(20-2)*180=18*180=3240 degrees

7. exterior angles add to 360
4y+2y+4y+6y=360
16y=360
y=22.5
2y=45 degrees
4y=90 degrees
6y=135 degrees

8. interior angles of 4 gon sum is
(4-2)*180=2*180=360
2n+6n+5n+2n=360
15n=360
n=24
2n=48
5n=120
6n=144

9.
6gon
(6-2)*180=4*180=720
90+90+x+x+22+x+x+22=720
224+4x=720
minus 224 both sides
4x=496
divide by 4
x=124

10., exterior angle of pentagon, 5 gon
360/5=72=x

11.
(n-2)*180/n=4*(360/n)
times both sides by n
(n-2)*180=4*360
divide both sides by 180
n-2=4*2
n-2=8
n=10
10 sides

12.
area of octogon of side is
</span>2(1+√2)s² where s is the side length
given, 12=side length
A=2(1+√2)12²
A=2(1+√2)144²
A=288(1+√2)
A=288+288√2 square cm

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A set of data has a normal distribution with a mean of 5.1 and a standard deviation of 0.9. Find the percent of data between 4.2

Yuliya22 [10]

A set of data has a normal distribution with a mean of 5.1 and a standard deviation of 0.9. Find the percent of data between 4.2 and 5.1.

Answer: The correct option is B) about 34%

Proof:

We have to find $P(4.2$