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Aneli [31]
3 years ago
15

If arc EF = 151°, find mEDF.

Mathematics
1 answer:
user100 [1]3 years ago
4 0
There is a theorem that says that this angle (formed by thre points on the circumference) is half such arc called EF.

We can deduct it as well.

1) Call O the center of the circle. The central angle (EOF) = arc EF = 151°

2) Draw a chord from F to D and other chord from D to E.

You have constructed two triangles, FOD and DOE.

3) Triangle FOD has two sides equals (because both are the radius of the circcle). Then, this is an isosceles triangle and it has two angles of the same measure. Call this measure a.

4) Triangle DOE is also isosceles, for the same reason explained in the poiint 3. Call the measure of its equal angles b.

5) The sum of the angles of the two triangles is 180° + 180 ° = 360°.

This is a + a + b + b + (360 - central angle) = 360°

=> 2a + 2b = central angle
=> 2(a+b) = cantral angle
=> (a+b) = central angle / 2 = 151° / 2 =71.5°

(a+b) is the angle that you are looking for.

Then the answer is 71.5°

 
You might be interested in
A. Find the amplitude.
Feliz [49]

Answers:

  • a) Amplitude = 2
  • b) Period = pi
  • c) Vertical shift = -2, which means it has been shifted down 2 units.
  • d) Horizontal shift = 3pi/8, this shifting is to the right.
  • e) There is <u>  one  </u> cycle between 0 and 2pi.
  • f) The equation of the graph is y = 2*sin(2(x-3pi/8))-2

========================================================

Explanations:

Part (a)

The highest point is when y = 0 and the lowest point is when y = -4. The vertical distance between the peak and valley is 4 units, which cuts in half to 2. This is the amplitude. It's the vertical distance from the center to either the peak or valley.

Note: Amplitude is always positive as it measures a distance.

---------------------

Part (b)

For x > 0, the first valley or lowest point occurs between 0 and pi/4. It appears to be the midpoint of the two values. So that would be (0+pi/4)/2 = pi/8.

The next valley occurs between pi and 5pi/4. Compute the midpoint to get (pi+5pi/4)/2 = (4pi/4+5pi/4)/2 = (9pi/4)/2 = 9pi/8

So we have the graph go from one valley x = pi/8 to the next valley over x = 9pi/8. This is a distance of pi units because 9pi/8-pi/8 = 8pi/8 = pi

The graph repeats itself every pi units, so the period is pi.

---------------------

Part (c)

The midline is normally through y = 0, aka the x axis. However, the graph shows the midline is through y = -2. This means the graph has been shifted down 2 units.

---------------------

Part (d)

This will depend on whether you use sine or cosine. This is entirely because cosine is a phase-shifted version of sine, and vice versa. I'll go with sine.

The parent sine function y = sin(x) goes through the origin (0,0)

However, as part (c) mentioned, we shifted the graph 2 units down. So we have y = sin(x)-2. But plugging x = 0 into this leads to the point (0,-2)

This doesn't match what the graph says. The graph shows the point (3pi/8, -2) on the red curve. The x coordinate 3pi/8 is the midpoint of pi/4 and pi/2

This must mean we need to shift the sine graph 3pi/8 units to the right.

---------------------

Part (e)

Start at the lowest point when x = pi/8. If you start the cycle here, then it ends when x = 9pi/8. See part (b).

So far we've completed one cycle. If we start at x = 9pi/8, then the next valley or lowest point is slightly beyond or to the right of x = 2pi. This means we run out of room and we haven't completed a full cycle.

Overall, one full cycle is between 0 and 2pi.

---------------------

Part (f)

Again I'm going to use sine instead of cosine. Refer back to part (d).

The general sine curve equation is

y = A*sin(B(x-C))+D

where

  • |A| = amplitude
  • B handles the period, specifically T = 2pi/B where T is the period. We can solve for B to get B = 2pi/T
  • C = horizontal phase shift
  • D = vertical shift, and ties together with the midline equation

In this case, we found that

  • |A| = 2
  • T = pi leads to B = 2pi/T = 2pi/pi = 2
  • C = 3pi/8
  • D = -2

So,

y = A*sin(B(x-C))+D

will update to

y = 2*sin(2(x-3pi/8))-2

which is one way to express the equation of the red curve. Optionally you can distribute the 2 through to (x-3pi/8).

6 0
2 years ago
What is the unit form using the largest unit possible for 4tens+6tens
Gre4nikov [31]
40 + 60 = 100

Hundrends place
4 0
3 years ago
Five more than a number is three
Pavel [41]

I'm not sure if you use "x" as your variable, so:

# + 5 = 3 or x + 5 = 3

7 0
3 years ago
Read 2 more answers
How much less would a 23-year-old female pay for a $25,000 policy of 20 year life insurance (@ $2.90 per $1000) than straight li
mojhsa [17]

<u>Answer</u>:

The female would pay  $322.00 less for a policy of $25,000

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

Since we have given that

Amount for policy = $25000

If she opt for 20 year life insurance at $2.90 per $1000.

so, her amount of premium becomes

25000\times \frac{2.9}{1000}

=$72.50

If she opt for straight life insurance at $15.78 per $1000,

Then, her amount of premium becomes

25000 \times \frac{15.78}{1000}

= $394.50

Difference between them is given by

$394.50-$72.5 = $322.00

5 0
3 years ago
Read 2 more answers
What is the slope of the line that passes through (-5,-2) and ( 7, -2)
denis23 [38]

。☆✼★ ━━━━━━━━━━━━━━  ☾  

slope = difference in y / difference in x

Sub the values in:

slope = (-2- -2) / (7 - -5)

slope = 0 / 12

The slope is 0.

Have A Nice Day ❤    

Stay Brainly! ヅ    

- Ally ✧    

。☆✼★ ━━━━━━━━━━━━━━  ☾

6 0
3 years ago
Read 2 more answers
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