CAN SOMEONE PLEASE HELP ME WITH THIS AND MAYBE THE REST?

The table shows the Webster family’s monthly expenses for the first three months of the year. They are $2,687.44, $2,613.09, and

zloy xaker [14]

8109.17 that is the answer if u add it

6 0

3 years ago

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To be considered for pilot school, 12 students took a spatial reasoning test that resulted in this list of scores. Find the valu

lord [1]

Answer:

the 90th percentile is 145

Step-by-step explanation:

Data provided:

152 121 130 143 122 101 137 98 138 127 145 117

Number of students considered, n = 12

To find:

90th percentile

Now,

Step 1 : Arrange the data in ascending order

98, 101, 117, 121, 122, 127, 130, 137, 138, 143, 145, 152

Step 2 : Compute the position of the 90th percentile

position of the 90th percentile, i = (90% × n)

Thus,

i = 0.90 × 12

or

i = 10.8

Now,

Step 3 : Since, the index i is not an integer, round up to the nearest integer

i.e i = 11

Therefore,

The 90th percentile is the value in 11th position,

i.e 145

7 0

2 years ago

How cos π/3=1/2?<br>having some problems learning continuity.

Bingel [31]

You can show that $\cos\frac\pi3=\frac12$ by constructing a triangle.

Take two points, O(0, 0) and A(1, 0), and let B be the point on the unit circle such that the angle between the line segments OA and OB is $\frac\pi3$ radians.

Since both A and B lie on the circle, the line segments OA and OB both have length 1 (same as the circle's radius). We finish constructing the triangle by connect A and B.

Since OB and OA have the same length, triangle OAB is isosceles, but more than that, it's also equilateral. Why? Because the interior angles of any triangle always add to $\pi$ radians. We know one of the angles is $\frac\pi3$ radians, which leaves a contribution of $\frac{2\pi}3$ radians between the remaining angles A and B. Angles A and B must be congruent (because OAB is isosceles), which means they also have measure $\frac\pi3$ radians.

Next, draw an altitude of the triangle through point B, and label the point where it meets the "base" OA, C. Since OAB is equilateral, the altitude BC is also a perpendicular bisector. That means OC has length $\frac12$ , and by definition of $\cos$ we have

$\cos\dfrac\pi3=\dfrac{OC}{OB}=\dfrac{\frac12}1=\dfrac12$

3 0

3 years ago

Eliminate the parameter. x = t2 + 2, y = t2 - 4

stepan [7]

$\bf \begin{cases}
x=t^2+2\implies x-2=t^2\implies \sqrt{x-2}=\boxed{t}\\\\
y=t^2-4\\
----------\\
y=\left( \boxed{\sqrt{x-2}} \right)^2-4\implies y=x-2-4\\\\
y=x-6
\end{cases}$

just a plain vanilla substitution

8 0

3 years ago

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The area of a rectangular plank is 4500 cm². The plank was broken into two pieces, one of which is a square and the other a rect

svp [43]

Answer:

$Xs=30cm$ and $As=900 cm^{2}$

Step-by-step explanation:

At=As+Ar; A=b.h and $At=4500 cm^{2}$ , then: At=(x+120)x so

(x+120)x=4500, $x^{2} +120x-4500=0$ Applying cuadratic equation formula: $\frac{120+-\sqrt{120^{2} -4.1.-4500} }{2} =-\frac{120+-\sqrt{14400+18000} }{2}= x1=30 and x2=-150, finally Xs=30cm, and As=900cm^{2}$

3 0

3 years ago

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