I'm trying to help My son out with his homework and I can't.. Sad to say... He has 20 problems and if someone can help explain one to me I should be able to help him with the reset.. I just need a guideline to go by..
Question 1 -
A map key shows that every 3 centimeters represents 60 miles. Which proportion could be used to determine the number of miles represented by 8 centimeters?
A - 60/3 = 8/m
B - 3/8 = m/60
C - 3/5 = 60/m
D - 3/60 = 8/m
I need to know HOW TO GET THE ANSWER not just the answer.. This way I can help him on the rest...
Thanks a bunch to anyone that can help..
2006-10-02 03:53:10 · 4 answers · asked by Abtram 4 in Education & Reference ➔ Teaching
The answer you want is a ratio: x miles per 8 centimeters. Ratios can be expressed as fractions, so our goal is
x miles
______
8 cm
We also have a second ratio: 3 cm per 60 miles. 3 cm per 60 miles is the same as 60 miles per 3 cm. Convert that to a fraction:
60 miles
_______
3 cm
Now, to solve.
60 miles $$ x miles
_______ = ______
3 cm $$$$ 8 cm
(Pretend the dollar signs don't exist--they're just there to get the fractions to line up.)
Solve for x miles. Multiply both sides by 8 cm to get
60 miles * 8 cm
____________ = x miles
3 cm
480 miles * cm
____________ = x miles
3 cm
160 miles * cm
____________ = x miles
cm
Anything/anything = 1 as long as the anything in question isn't zero.
2/2 = 1.
3/3 = 1.
It doesn't even have to be numbers. Units work as well.
mile(s)/mile(s) = 1
pizza(s)/pizza(s) = 1
And, the one we're interested in right now:
cm/cm = 1
We can replace cm/cm with 1/1.
180 miles * 1 = x miles.
__________
1
The answer is 180 miles.
2006-10-02 04:49:48 · answer #1 · answered by yetanotheronlinename 2 · 0⤊ 0⤋
(correction)
D.
I thinks it's called a ratio. (I'm rusty)
3 cm is to 60 miles as 8 cm is to m miles.
Solve for m
(3/60)/8 = m
(1/20)x (1/8) = m
Or, every cm is 20 miles. So, 8 cm is 160 miles
2006-10-02 04:04:01 · answer #2 · answered by Anonymous · 0⤊ 0⤋
the answer is A (i do believe anyway) .
3cm=60miles
so divide 60 by 3 (60/3) to get what 1cm is equal to
then therefore it'd be 8 times that to know the equivalent of what 8cms would be.
2006-10-02 04:05:14 · answer #3 · answered by *MaE* 3 · 0⤊ 0⤋
Try this website
http://mathforum.org/dr.math/
He will explain how
2006-10-02 04:22:11 · answer #4 · answered by Sky B 3 · 0⤊ 0⤋