1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
KiRa [710]
2 years ago
13

Item 7

Mathematics
1 answer:
Mariulka [41]2 years ago
8 0

Answer:

A = 74.7^\circ

B = 42.5^\circ

C = 62.8^\circ

Step-by-step explanation:

Given

A = (-1,2) \to (x_1,y_1)

B = (2,8) \to (x_2,y_2)

C = (4,1) \to (x_3,y_3)

Required

The measure of each angle

First, we calculate the length of the three sides of the triangle.

This is calculated using distance formula

d = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2

For AB

A = (-1,2) \to (x_1,y_1)

B = (2,8) \to (x_2,y_2)

d = \sqrt{(-1 - 2)^2 + (2 - 8)^2

d = \sqrt{(-3)^2 + (-6)^2

d = \sqrt{45

So:

AB = \sqrt{45

For BC

B = (2,8) \to (x_2,y_2)

C = (4,1) \to (x_3,y_3)

BC = \sqrt{(2 - 4)^2 + (8 - 1)^2

BC = \sqrt{(-2)^2 + (7)^2

BC = \sqrt{53

For AC

A = (-1,2) \to (x_1,y_1)

C = (4,1) \to (x_3,y_3)

AC = \sqrt{(-1 - 4)^2 + (2 - 1)^2

AC = \sqrt{(-5)^2 + (1)^2

AC = \sqrt{26

So, we have:

AB = \sqrt{45

BC = \sqrt{53

AC = \sqrt{26

By representation

AB \to c

BC \to a

AC \to b

So, we have:

a = \sqrt{53

b = \sqrt{26

c = \sqrt{45

By cosine laws, the angles are calculated using:

a^2 = b^2 + c^2 -2bc \cos A

b^2 = a^2 + c^2 -2ac \cos B

c^2 = a^2 + b^2 -2ab\ cos C

a^2 = b^2 + c^2 -2bc \cos A

(\sqrt{53})^2 = (\sqrt{26})^2 +(\sqrt{45})^2 - 2 * (\sqrt{26}) +(\sqrt{45}) * \cos A

53 = 26 +45 - 2 * 34.21 * \cos A

53 = 26 +45 - 68.42 * \cos A

Collect like terms

53 - 26 -45 = - 68.42 * \cos A

-18 = - 68.42 * \cos A

Solve for \cos A

\cos A =\frac{-18}{-68.42}

\cos A =0.2631

Take arc cos of both sides

A =\cos^{-1}(0.2631)

A = 74.7^\circ

b^2 = a^2 + c^2 -2ac \cos B

(\sqrt{26})^2 = (\sqrt{53})^2 +(\sqrt{45})^2 - 2 * (\sqrt{53}) +(\sqrt{45}) * \cos B

26 = 53 +45 -97.67 * \cos B

Collect like terms

26 - 53 -45= -97.67 * \cos B

-72= -97.67 * \cos B

Solve for \cos B

\cos B = \frac{-72}{-97.67}

\cos B = 0.7372

Take arc cos of both sides

B = \cos^{-1}(0.7372)

B = 42.5^\circ

For the third angle, we use:

A + B + C = 180 --- angles in a triangle

Make C the subject

C = 180 - A -B

C = 180 - 74.7 -42.5

C = 62.8^\circ

You might be interested in
A similarity ratio is the ratio of the lengths
kow [346]
Similarity ratio is a ratio of two figures having the same side.

Ratio can be rate but rate can never be ratio. In essence, rate is comparison between ratios.  While ratio is comparison between two or more numbers. Further, ratio on one hand, involves numbers either in amount, size, measurement, degrees, percentages or fractions with the absence of specific unit of measurement. On the contrary, rate is comparing quantities, amounts or unit of events happened expressed in a specific measurement or expressed under time. Take for instance, an example, Joe eats 2 while John eats 4 meals in a day. The ratio can be Joe: John, 2:4 meals. While the rate, is Joe eats 2 meals/day and John 4 meals/day.<span>
</span>
7 0
3 years ago
For which rational expression is –2 an excluded value of x?
statuscvo [17]
Answer is A 
X-3/x^2-4 has two excluded values 2, -2
4 0
3 years ago
Find x plss:))))))))
Galina-37 [17]

Answer:

180 - 90 = 90

half of 90 = 45

40 and 50??

Step-by-step explanation:

6 0
3 years ago
Read 2 more answers
A student dropped a textbook from the top floor of his dorm and it fell according to the formula s(t) = −16t 2 + 8√t , where t i
Sidana [21]

Answer:

<h2>-29.61m/s</h2>

Step-by-step explanation:

Given the distance of fall of the student in term of the time t expressed by the equation s(t) = −16t² + 8√t, to get the average speed of fall of the pencil after 2.8 secs, we will need to differentiate the given function first since Velocity is the change in distance of a body with respect to time i.e

V = d(s(t))/dt

s(t) = −16t² + 8t^1/2

V = -32t+1/2(8)t^(1/2 - 1)

V = -32t+4t^-1/2

The average speed of the fall Using the fact that the pencil hit the ground in exactly 2.8 seconds, will be gotten by substituting t = 2.8 into the resulting equation.

V = -32t+4(2.8)^-1/2

V = -32t+4/√2.8

V = -32+4/1.6733

V = -32+2.391

v = -29.61m/s

<em>Hence the average speed of the fall is -29.61m/s</em>

3 0
3 years ago
A researcher asks random samples of residents of two separate counties as to whether they had purchased organically grown food i
Leni [432]

Answer:

2 proportions z test

The two populations are named as residents from the first county and residents from the second county.

Step-by-step explanation:

This is testing hypothesis about the difference between two proportions.

When the proportions are tested if they are the test statistic

z= ( p^1-p^2)- (p1-p2) / √p₁q₁/n₁ + p₂q₂/ n₂

where p^1 is the proportion of success in the first sample and   p^2 of size n₁   is the proportion of success in the second sample of size n₂ with unknown proportions of successes p1 and p2 respectively.

When the sample sizes are sufficiently large

z= ( p^1-p^2)- (p1-p2) / √p₁q₁/n₁ + p₂q₂/ n₂ is approximately standard normal.

The two populations are named as residents from the first county and residents from the second county.

7 0
3 years ago
Other questions:
  • A bike shop rents bikes for $4.50 per hour, plus a $7.50 insurance charge. For how many hours can Peter rent a bike if he has $3
    6·1 answer
  • Factor completely x3 − 2x2 − 5x + 10.
    12·1 answer
  • Solve for n. 583 = (n ÷ 10) + 3
    15·2 answers
  • 3(2x+9) = 4+3x-1<br><br> What does x equal
    15·2 answers
  • In a small town, there are 4 times as many left-handed males as there are left-handed females, and there are 3 times as many rig
    5·1 answer
  • What is an unbrocken part of a circle called
    15·1 answer
  • Two tanks are being filled. Tank 1 is being filled at a rate of 3/4 gallon per 2/3minute
    9·1 answer
  • Show whether or not the points with coordinates (1,3) (4,2) (-2,6) are vertices of a right triangle
    6·1 answer
  • 100 points !!!!! thank you :)
    15·2 answers
  • Two friends share £150 in the ratio 4:11<br> (a) How much does each friend receive?
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!