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3 years ago

The mean of 4 test scores is 90. What is the sum of the scores?

2 answers:

6 0

To find a mean of a number or the average you first would add all the test scores up. then divide by the number of the quantity there are.
* the quantity is 4
so before you divide by the quantity you already added the sum of the test so if you do the problem backward and instead of dividing by 4 you would multiply by 4.

So 90 times 4 which is 360.
Thus the sum of the score is 360.

shepuryov [24]3 years ago

5 0

360.
A general rule of thumb when dealing with questions like these is using the following equation:

(number of numbers) x (mean) = sum of numbers

Proof/Example: 7, 10, 13
There are 3 numbers here and the mean is 10. Multiply them together and you will get 30, just as you will get 30 from adding them together.

In this case, there are 4 numbers and the mean is 90, so 4 x 90 = 360.

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Find the area of a triangle with:

telo118 [61]

Answer:

161cm2

Step-by-step explanation:

Area: 1/2 x base x height

1/2 x 14 x 23=161

Area is measured in cm2

Hope this helps!

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2 years ago

Steven put together 981 pieces of a puzzle. About how many pieces did he put together? Round to the nearest thousand. Use what y

Colt1911 [192]

About 1,000 puzzle pieces

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2 years ago

Triangle- interior angle<br> Please help !

sp2606 [1]

Answer:

x = 25

<B = 120 degrees

<C = 30 degrees

Step-by-step explanation:

Total angle measure of a triangle - 180 degrees

Add all the angles together to find the value of x

30 + 4x + 20 + x + 5 = 180

55 + 5x = 180

55 - 55 + 5x = 180 - 55

5x = 125

$\frac{5x}{5} = \frac{125}{5}$

x = 25

<B = 4(25) + 20

<B = 100 + 20

<B = 120

<C = 25 + 5

<C = 30

7 0

3 years ago

Use the discriminant to describe the roots of each equation. Then select the best description. 2 = x2 + 5x. A) Double root B) Re

fredd [130]

$\bf 2=x^2+5x\implies 0=x^2+5x-2\\\\\\\qquad \qquad \qquad \textit{discriminant of a quadratic}\\\\\\0=\stackrel{\stackrel{a}{\downarrow }}{1}x^2\stackrel{\stackrel{b}{\downarrow }}{+5}x\stackrel{\stackrel{c}{\downarrow }}{-2}~~~~~~~~\stackrel{discriminant}{b^2-4ac}=\begin{cases}0&\textit{one solution}\\positive&\textit{two solutions}\\negative&\textit{no solution}\end{cases}\\\\\\(5)^2-4(1)(-2)\implies 25+8\implies 33$

so we have a 33, namely two real solutions for that quadratic.

usually that number goes into a √, if you have covered the quadratic formula, you'd see it there, namely that'd be equivalent to √(33), now 33 is a prime number, and √(33) is yields an irrational value, specifically because a prime number is indivisible other than by itself or 1.

so 33 can only afford us two real irrational roots.

3 0

2 years ago

Triangle XYZ is shown, where n ≥ 5. Triangle X Y Z is shown. The length of side X Y is n + 4, the length of side Y Z is 2 n, and

motikmotik

Answer:

The longest side of the triangle is YZ, the shortest side is ZX, the largest angle is ∠X and the smallest angle is ∠Y.

Step-by-step explanation:

The lengths of the sides of the triangle XYZ are as follows:

XY = n + 4

YZ = 2n

ZX = n - 2

According to the triangle inequality theorem, the sum of two sides of a triangle is always greater than the third side.

Then,

XY < YZ + ZX ⇒ n + 4 < 2n + n - 2 ⇒ n + 4 < 3n - 2 ⇒ 2n > 6 ⇒ n > 3

YZ < XY + ZX ⇒ 2n < n + 4 + n - 2 ⇒ 2n < 2n + 2 ⇒ 0 < 2

ZX < XY + YZ ⇒ n - 2 < n + 4 + 2n ⇒ n - 2 < 3n + 4 ⇒ 2n > -6 ⇒ n > -3

It is provided that <em>n</em> ≥ 5.

Then the sides of the triangle are:

XY = n + 4 ≥ 5 + 4 = 9

YZ = 2n ≥ 2 × 5 = 10

ZX = n - 2 ≥ 5 - 2 = 3

So, the longest side of the triangle is YZ. And the shortest side is ZX.

The largest angle of a triangle is opposite to the longest side.

The angle opposite to YZ would be X. So, the largest angle is ∠X.

The smallest angle of a triangle is opposite to the shortest side.

The angle opposite to ZX would be Y. So, the smallest angle is ∠Y.

Thus, the longest side of the triangle is YZ, the shortest side is ZX, the largest angle is ∠X and the smallest angle is ∠Y.

6 0

3 years ago