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3 years ago

Mr. Jacobs has 5 math classes. He teaches a total of 30 boys and 45 girls.

Mathematics

1 answer:

Katyanochek1 [597]3 years ago

8 0

Answer:

30 :75

Step-by-step explanation:

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Please help me with segment addition and midpoints

Tanya [424]

Answer:

Step-by-step explanation:

Since we know QR and RS are the same, we can add them together

6 + 6 = 12

Since the whole line is 15 we subtract 12 from 15

15 - 12 = 3

8 0

2 years ago

1.7 In the following diagram, angle 7 equals 61°.

gladu [14]

1.7) < 7 and < 8 form a linear pair....which means, when added, they equal 180 degrees. So if < 7 = 61, then < 8 = (180 - 61) = 119 <=

1.8) angles that are supplementary will add up to 180. So if one of the angles is 38, then the other one is (180 - 38) = 142 <==

1.9) < 3 = < 5 (vertical angles are congruent)
1.10) < 2 = < 8 (vertical angles are congruent)
1.11) < 7 = < 1 (vertical angles)
1.12) < 6 = < 4 (vertical angles)

7 0

3 years ago

Read 2 more answers

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

3 years ago

Find an expression for the area enclosed by quadrilateral ABCD below.

Helga [31]

∆ABD is right angled hence area:-

$\\ \sf\longmapsto \dfrac{1}{2}bh$

$\\ \sf\longmapsto \dfrac{1}{2}(4x)(3x)$

$\\ \sf\longmapsto \dfrac{1}{2}(12x^2)$

$\\ \sf\longmapsto 6x^2$

There is only one option containing 6x^2 i.e Option D.

Hence without calculating further

Option D is correct

6 0

3 years ago

Read 2 more answers

Which expression is equivalent to x + y + x + y + 3(y + 5)? 2x + 5y + 5 2x + y + 30 2x + 5y + 15 2x + 3y + 10 NextReset

jolli1 [7]

<span>Which expression is equivalent to x + y + x + y + 3(y + 5)? 2x + 5y + 5 2x + y + 30 2x + 5y + 15 2x + 3y + 10

</span> $x + y + x + y + 3(y + 5)= \\ \\ x+y+x+y+3y+15= \boxed{ 2x+5y+15 }$ <span>
</span>

7 0

3 years ago

Read 2 more answers