1. ## Proportions

1. 3/x=x/?

2. 3/?=?/10

3. 13/z=z/?

4. ?/y=y/10

5. 10/?=?/13

6. 13/?=?/3

These proportions are very strange to me, but its the way the book has it layed out.

Directions say use theorems 7.2 and 7.3 which make no sense to me, but here they are:

7.2 In a right triangle, the length of the altitude to the hypotenuse is the geometric mean between the lengths of the two segments on the hypotenuse.

7.3 In a right triangle with an altitude to the hypotenuse, each leg is the geometric mean between the sum of the squares of the lengths of the legs.

2. i guess my question is how do you find the ? for a problem like 3/x=x/?

once i know how to find the ? i can take it from there

3. Originally Posted by OzzMan
i guess my question is how do you find the ? for a problem like 3/x=x/?

once i know how to find the ? i can take it from there
I would replace the ? with a variable, say y:
$\displaystyle \frac{3}{x} = \frac{x}{y}$

Multiply both sides by xy:
$\displaystyle 3y = x^2$ <--Otherwise known as "cross-multiplication."

$\displaystyle y = \frac{x^2}{3}$

You can do this kind of thing with all of them.

-Dan

4. Wow another easy problem. Thanks for the help. The book was dumb imo to have ? marks instead of lettered variables.

5. nvm these problems arent done by cross multiplication. i checked the answer in the back of the book and they got non variable answers for both variables. so i really have no idea now.

6. Originally Posted by OzzMan
nvm these problems arent done by cross multiplication. i checked the answer in the back of the book and they got non variable answers for both variables. so i really have no idea now.
What answer does the book give?

7. the books answer for the first one is 10, x=square root of 30

which im assuming the 10 is for the ?

but how are these answers correct. i see no logical way of them being correct. anyone know ?

8. Originally Posted by OzzMan
the books answer for the first one is 10, x=square root of 30

which im assuming the 10 is for the ?

but how are these answers correct. i see no logical way of them being correct. anyone know ?
No i cannot see why it would be those answers specifically either.

9. yes biggest question is how did they get 10 for the ? makes no sense.

10. Sorry to post again on this post but if anyone knows how to do this, could you help me out. I'm really lost with this. Mostly how they solve for the ? in the first one.

11. Originally Posted by OzzMan
Sorry to post again on this post but if anyone knows how to do this, could you help me out. I'm really lost with this. Mostly how they solve for the ? in the first one.
You'll get an infraction for bumping

No, honestly I cannot see how they got those values.
These equations can be satisfied with just about any value. (Although it seems it has to be only positive values)