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2 years ago

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Ella’s test grades in her history class are 89, 94, 82, 84, and 98. What score must Ella make on her next test to have a mean te

st score of 90?

1 answer:

Stells [14]2 years ago

4 0

Answer:

the answer is 93

Step-by-step explanation:

mean of x,y,z

x+y+z

3 terms

(x+y+z)/3=mean

so

represent next test score as x

89+94+82+84+98+x

count how many terms ther are (6 terms)

mean is 90

(89+94+82+84+98+x)/6=90

add the like terms

(447+x)/6=90

multiply both sides by 6 to clear fraction

447+x=540

subtract 447 from both sides

x=93

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Need help on these trig homework

allochka39001 [22]

8. The length of the support is 7. 9 m

9. The length of the conveyer is 12m

3. a = 59m

A = 44°

B = 52°

4. c = 88. 6 mm

b = 49. 1 m

B = 34°

<h3>How to solve the trigonometry</h3>

8. We have the angle to be 20 degrees

Opposite side = x

hypotenuse = 23m

Using the sine ratio

sin θ = opposite/ hypotenuse

$sin 20 = \frac{x}{23}$

Cross multiply

$sin 20$ × $23 = x$

$x = 0. 3420$ × $23$

x = 7. 9 m

The length of the support is 7. 9 m

9. The angle of elevation is 37. 3 degrees

Hypotenuse = 19 . 0m

Opposite = x

Using the sine ratio

sin θ = opposite/ hypotenuse

$sin 37. 3 = \frac{x}{19}$

cross multiply

$x = 0. 6059$ × $19$

x = 11.5

x = 12 m in 2 significant figures

The length of the conveyer is 12m

3. To determine the sides and angles, we use the sine rule;

$\frac{a}{sin A} = \frac{b}{sin B} = \frac{c}{sin C}$

For side a, we use the Pythagorean theorem

$c^2 = a^2 + b^2$

$85^2 = a^2 + 67^2$

$a = \sqrt{89^2-67^2}$

$a = \sqrt{3432}$

a = 58. 58, a = 59m

To find angle A and B, use the sine rule

$\frac{59}{sin A } = \frac{85}{sin 90}$

cross multiply

$sin A$ × $85$ = $sin 90$ × $59$

make sin A subject of formula

$sin A = \frac{59}{85}$

$sin A = 0. 6941$

A = $sin^-^1(0. 6941)$

A = 44°

$\frac{67}{sin B} = \frac{85}{sin 90}$

cross multiply

$sin B$ × $85$ = $sin 90$ × $67$

make sin b subject of formula

$sin B = \frac{67}{85}$

$sin B = 0. 7882$

B = $sin^-^1( 0. 7882)$

B = 52°

4. To find the sides, we use the sine rule;

$\frac{74. 0}{sin 56. 6} = \frac{c}{sin 90}$

Cross multiply

$sin 56. 6$ × $c = sin 90$ × $74$

make 'c' subject of formula

$c = \frac{74}{0. 8348}$

c = 88. 6 mm

To find length b, we use the Pythagorean theorem

$c^2 = a^2 + b^2$

$b^2 = c^2 - a^2$

$b^2 = 88. 8^2 - 74^2$

$b = \sqrt{7885. 44 - 5476}\\\\ b = \sqrt{2409. 44}$

b = 49. 1 m

$\frac{74. 0}{sin 56. 6} = \frac{49. 1}{sin B}$

cross multiply

$sin B = \frac{40. 99}{74. 0}$

B = $sin^-^1(0. 5539)$

B = 34°

Learn more about trigonometric identity here:

brainly.com/question/7331447

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3 0

1 year ago

30 POINTS HELP PLEASE

Reptile [31]

Answer:

$\large\boxed{a=-3,\ b=-7\ and\ c=3}$

Step-by-step explanation:

$ax^2+bx+c=0$

We have:

$-3a^2=7a-3$ <em> subtract 7a from both sides</em>

$-3a^2-7a=7a-7a-3$

$-3a^2-7a=-3$ <em>add 3 to both sides</em>

$-3a^2-7a+3=-3+3\\\\-3a^2-7a+3=0\to a=-3,\ b=-7, c=3$

8 0

3 years ago

Adrian is putting streamers across the ceiling of his dining room to decorate for his nephew’s birthday party. The ceiling is re

ale4655 [162]

Answer: hello there here is your answer:

17.5 feet

Step-by-step explanation:

Area of rectangle = Length x Width

Length = Area/Width = 122.5 / 7 = 17.5 feet

hope this helps

have a god day bye

7 0

2 years ago

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1.Which of the following is equivalent to 0.00648

kolbaska11 [484]

Answer:

qd5g

Step-by-step explanation:

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2 years ago

Which expression is represented by the diagram? 10 negative tiles. 4 are crossed out. Negative 6 minus (negative 4) Negative 6 m

PolarNik [594]

<h3>These all can be reperseted by diagram</h3>

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3 years ago

Read 2 more answers