I need some Pre-Calc help
These are the questions.
Last year, Phil planted carrots in a square shaped plot, with sides measuring 18ft. This year, he changed this plot into a rectangular design with the same area as the original square section. If the new width of this section is 12ft, what is its length in feet?
A line in the coordinate plane has a slope of (3/2) and goes through the point (-3,-2). If the point with coordinates (a,70 is on the line, then a=?
September 12, 2012
5 Comments • Newest first
[quote=zippinbolts]Fixed, all you needed to do was divide the final answer by 10.[/quote]
thank you, sensei
[quote=zippinbolts]TS: Is this Pre-calc. I find this mind blowing.[/quote]
Yup, well this is some old review test we're taking.
Thanks a lot guys!
for the first one, area is 18x18, since it is a square. the area is 324ft squared.
if the new place has the same area and the width is 12ft, just divide 324/12 because
LxW=A
your width is 12, and area is 324, so you solve for L
L=A/W=324/12=27ft
your length is 27 feet.
Phil's question:
A square's area is given by any length it has squared.
The area was thus 18^2 or 324.
A rectangle's area is given by (length)*(width)
You know the area is the same as the previous plot.
324 = length*12
324 = 12x
Solve for x
The line question:
Equation of a line: y = mx + b
Slope, m, is 3/2 and you are given two points, therefore giving you (x,y)
-2 = (3/2)(-3) + b
Solve for b and it should give you 5/2.
This means the general equation of this line is y = (3/2)x + 5/2
Now input the information from the new point:
70 = (3/2)a + 5/2
Solve for a.