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3 years ago

Math work 7th grade

Mathematics

1 answer:

dem82 [27]3 years ago

6 0

Answer:

-50

Step-by-step explanation:

since its diving down, take -32 and subtract 18. -50. Lemme know if this helps!

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Help! Will mark brainliest!

miss Akunina [59]

Answer: a rise of 12 and a run of 7

Step-by-step explanation:

7 0

2 years ago

Please dont ignore, Need help!!! Use the law of sines/cosines to find..

Ket [755]

Answer:

16. Angle C is approximately 13.0 degrees.

17. The length of segment BC is approximately 45.0.

18. Angle B is approximately 26.0 degrees.

15. The length of segment DF "e" is approximately 12.9.

Step-by-step explanation:

By the law of sine, the sine of interior angles of a triangle are proportional to the length of the side opposite to that angle.

For triangle ABC:

$\sin{A} = \sin{103\textdegree{}}$ ,
The opposite side of angle A $a = BC = 26$ ,
The angle C is to be found, and
The length of the side opposite to angle C $c = AB = 6$ .

$\displaystyle \frac{\sin{C}}{\sin{A}} = \frac{c}{a}$ .

$\displaystyle \sin{C} = \frac{c}{a}\cdot \sin{A} = \frac{6}{26}\times \sin{103\textdegree}$ .

$\displaystyle C = \sin^{-1}{(\sin{C}}) = \sin^{-1}{\left(\frac{c}{a}\cdot \sin{A}\right)} = \sin^{-1}{\left(\frac{6}{26}\times \sin{103\textdegree}}\right)} = 13.0\textdegree{}$ .

Note that the inverse sine function here $\sin^{-1}()$ is also known as arcsin.

By the law of cosine,

$c^{2} = a^{2} + b^{2} - 2\;a\cdot b\cdot \cos{C}$ ,

where

$a$ , $b$ , and $c$ are the lengths of sides of triangle ABC, and
$\cos{C}$ is the cosine of angle C.

For triangle ABC:

$b = 21$ ,
$c = 30$ ,
The length of $a$ (segment BC) is to be found, and
The cosine of angle A is $\cos{123\textdegree}$ .

Therefore, replace C in the equation with A, and the law of cosine will become:

$a^{2} = b^{2} + c^{2} - 2\;b\cdot c\cdot \cos{A}$ .

$\displaystyle \begin{aligned}a &= \sqrt{b^{2} + c^{2} - 2\;b\cdot c\cdot \cos{A}}\\&=\sqrt{21^{2} + 30^{2} - 2\times 21\times 30 \times \cos{123\textdegree}}\\&=45.0 \end{aligned}$ .

For triangle ABC:

$a = 14$ ,
$b = 9$ ,
$c = 6$ , and
Angle B is to be found.

Start by finding the cosine of angle B. Apply the law of cosine.

$b^{2} = a^{2} + c^{2} - 2\;a\cdot c\cdot \cos{B}$ .

$\displaystyle \cos{B} = \frac{a^{2} + c^{2} - b^{2}}{2\;a\cdot c}$ .

$\displaystyle B = \cos^{-1}{\left(\frac{a^{2} + c^{2} - b^{2}}{2\;a\cdot c}\right)} = \cos^{-1}{\left(\frac{14^{2} + 6^{2} - 9^{2}}{2\times 14\times 6}\right)} = 26.0\textdegree$ .

For triangle DEF:

The length of segment DF is to be found,
The length of segment EF is 9,
The sine of angle E is $\sin{64\textdegree}}$ , and
The sine of angle D is $\sin{39\textdegree}$ .

Apply the law of sine:

$\displaystyle \frac{DF}{EF} = \frac{\sin{E}}{\sin{D}}$

$\displaystyle DF = \frac{\sin{E}}{\sin{D}}\cdot EF = \frac{\sin{64\textdegree}}{39\textdegree} \times 9 = 12.9$ .

7 0

2 years ago

Is anyone good at paralleligram?!I will mark brainlest.for 13 points

Black_prince [1.1K]

Answer:

Y= 15

x = 12

Step-by-step explanation:

Okay, so the sides that are across from eachother, are always equal to eachother, in a parallelogram.

So, 5y-20 = 2y + 25

Next, you add 20 to both sides, and then subtract 2 from the right side, and subtract 2 from the left side ,and you get 3y = 45

divide 45 by 3 , and you get 15.

DO the same thing for the X's.

4 0

2 years ago

PLEASE HELP ME ASAP ITS TIMED

WINSTONCH [101]

Answer:

The solution is (2, 1).

All other ordered pairs do not work.

Step-by-step explanation:

-2x + 5y = 1

5x - 3y = 7

-10x + 25y = 5

10x - 6y = 14

19y = 19

y = 1

5x - 3(1) = 7

5x = 10

x = 2

(2, 1)

The solution is (2, 1).

All other ordered pairs do not work.

3 0

2 years ago

Dilate the circle using center (0,0) and scale factor 2<br> Pls help

gladu [14]

Answer:

look at image

Step-by-step explanation:

you're just making the circle twice as big. so since one of the points of the circle is (0,2) it would now be, (0,4) because 2 x 0 = 0 and 2 x 2 = 4.

6 0

2 years ago