Chris

Shoe Size 9.5 8.5 12 11.5 13.5 Height (in) 63.7 62.4 69.4 71.5 71.9 Use your calculator to determine the y-intercept of this scatterplot

Using shoe size as the independent variable (x) and height as the dependent variable (y), we have

y = 2.084375x + 44.8518

The y intercept is just the point (0, 44.8518)

If height 1s the dependent variable (x) and shoe size as the independent variable (y), we have

y = 0.422002x  -17.603

 The y intercept here is just (0, -17.603)

(Because the y intercept in the second function is negative, I suspect that shoe size is "x" and height is "y")

BTW....here is an online website that will do this for you.....make sure you don't have any spaces between the "x" and "y" values.......just a comma!!!

http://knowpapa.com/trend-line/

A clock has a radius of 9 inches. If it's 4:00, what's the arc length and the area of the sector of this time? 

I'm assuming that you want the arc length and area of the sector from 12 to 4.

Since this sector represents 1/3 of the total area of the clockface, it must also have an arc length of 1/3 of the total circumference of the clock.

The total circumference is given by 2*pi*9 in = 18pi inches

So 1/3 of the circumference = 6pi inches

And the total area is given by pi * (9 in)^2 = 81pi in^2

And 1/3 of this is just 27pi in^2

The area of one piece of pizza is 9π in^{2 . The pizza is cut into eighths. What's the radius of the pizza pie?} 

Well.....if 9π in² represents 1/8 of the area, then the total area must be 8 times as much...i.e., 72π in²

So we have that the area of a circle is given by......  A = πr²

Therefore

72π in² = πr²

Dividing by pi on each side, we have

72 in² = r²

Taking the square root of both sides, we have   

r = √(72)in = 6√(2) in

sin2x-sinx=0

Let's use an identity for sin(2x)......this = 2 sinxcosx

So we have

2sinxcosx - sinx = 0........let's factor out the sin x....so we have

sinx (2cosx -1) = 0

Setting each factor to 0, we have

sinx = 0  and 2cosx -1 =0

Solving the first, we have x = 0 + (pi)n

Solving the second, we have

cosx = 1/2

so x = (-pi/6) + 2(pi)n

and x = (pi/6) + 2(pi)n

Just take his earnings and divide by the hours he worked

what is the break even point of c=5.50+700 and r=9n

I'm not sure, but I think you meant the cost function to be c=5.50n+700, where 5.50n is the variable cost and 700 is the fixed cost...(I'm going to assume so)

Let's just set the equations equal and find the break-even point....so we have

5.50n+700 = 9n

Let's subtract 5.50n from both sides...we get

700 = 3.50n.....now divide both sides by 3.50...this gives

700/3.50 = n = 200 units

And that's it !!!

What is the value of x? If 22=125-x/2

First, let's subtract 125 from both sides...we get

-103 = -x / 2....now multipy both sides by 2

-206 = -x

Then x = 206

The largest Egyptian pyramid is 146.5 meters high. When Rowena stands far away from the pyramid her sight line to the top of the pyramid forms and angle of elevation of 20 degrees with the ground. What is the horizontal distance between the center of the pyramid and Rowena? Round to the nearest meter.

Let's use the tangent here...we have

tan(20º) = 146.5m / x....therefore,

x = 146.5m / tan(20) = 402.5m ≈ 403m

Bring back the Private Messaging...it is sometimes very helpful to be able to communicate with the other users !!! Plus...airing all our gripes about the new system on the Forum pages coudn't inspire much confidence in the people who have questions......

atan(22/11) = atan (2) = 63.434948822922º

Mmmmm.....looks perfectly valid, IMHO......(We're just asking ourselves, where does the tangent = 2 ??......Note that it has to be greater than 45º but < 90°)