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2 years ago

Jill bikes 2/3 hour at 18 mph and then walks 2/5 hour at 5 mph. How much farther did she bike than walk?

Mathematics

1 answer:

Oksana_A [137]2 years ago

8 0

Answer:

Step-by-step explanation:

When the equation says that Jill bikes 2/3 hour at 18 mph, it means that the amount of miles she biked is 2/3 of 18. 18 divided by 3 is 6. 6 times 2 is 12, so she biked 12 miles. If she walks 2/5 hour at 5 mph, then she walked 2 miles because 5 divided by 5 is 1 and 1 times 2 is two. The question is asking how much more she biked than walked, so 12-2=10.

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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

Which function graph has axis of symmetry x=2

Reptile [31]

Answer:

HJVJKN ,KMN,. MN

Step-by-step explanation:

3 0

4 years ago

2.2 Your friend Sam, mistakenly wrote down the multiples of 10 as: 1; 2; 5; and 10.

kkurt [141]

Do you know the multiples of 10

6 0

2 years ago

A survey was conducted

inna [77]

Answer: 9/25 or 36%

Step-by-step explanation:

72 + 28 + 62 + 38 = 200

There are 200 people in total and 72 are youngsters who like sport cars.

So, the number of youngsters who like cars out of the total number of people is 72/200.

Now, find a greatest common divisor. In this case, the greatest common divisor is 8.

72 / 8 = 9

200 / 8 = 25

9/25 (fraction)

25 * 4 = 100

9 * 4 = 36

36/100 = 36% (percentage)

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4 years ago

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Solve (2x + 5)= (2x + 3)(2x - 1)

AlexFokin [52]

$(2x + 5)= (2x + 3)(2x - 1)\\2x+5=4x^2-2x+6x-3\\4x^2-2x+6x-3-2x-5=0\\4x^2+2x-8=0\\(4x+1-\sqrt{33})( 4x+1+\sqrt{33})=0 \\ x=\frac{-1+\sqrt{33} }{4} /or/x=\frac{-1-\sqrt{33} }{4}$

4 0

2 years ago

Read 2 more answers