# Thread: How to know if this Square is Similer.

1. ## How to know if this Square is Similer.

Hey I need to know how these rectangles are similar if they are. Can anyone explain to me?

I made the photo on Paint so sorry if its bad xD.

2. Originally Posted by BostonKreme
Hey I need to know how these rectangles are similar if they are. Can anyone explain to me?

I made the photo on Paint so sorry if its bad xD.

Hi BostonKreme,

Polygons are similar if all the corresponding angles are congruent and all the corresponding sides are proportional.

Do your two figures meet both these conditions?

3. The angles are the same because there both rectangles. But I don't know how to find if the corresponding sides are proportional. Will only having the same angles prove that they are similar?

4. Originally Posted by BostonKreme
The angles are the same because there both rectangles. But I don't know how to find if the corresponding sides are proportional. Will only having the same angles prove that they are similar?
Well, you're right about the angles. Now, pair corresponding sides as ratios and see if they are equivalent.

Does $\displaystyle \frac{15}{8}=\frac{10}{4}$?

5. yes they do thx a bunch ^^.

6. Originally Posted by BostonKreme
yes they do thx a bunch ^^.
They do?!?

Better check again.

7. Lol i rechecked befor i handed my excises in and fixed it. thx a bunch

I also have one more problem that's stumping me can yah please help me out on this one.

AE intersects BD on point C. The two triangels are similar, AB = 15cm and
3CD = 4BC. I need to find out DE. my guess is that i haev to put 4x on the BC and 3x on the CD but then when i did it the way you showed me there to find the side i come up with 2 letters(the x from the 4x and the 3x and the y from the side i have to find) how could i find the y whitch is ED in this firgure.

heres the picture.

8. Originally Posted by BostonKreme
Lol i rechecked befor i handed my excises in and fixed it. thx a bunch

I also have one more problem that's stumping me can yah please help me out on this one.

AE intersects BD on point C. The two triangels are similar, AB = 15cm and
3CD = 4BC. I need to find out DE. my guess is that i haev to put 4x on the BC and 3x on the CD but then when i did it the way you showed me there to find the side i come up with 2 letters(the x from the 4x and the 3x and the y from the side i have to find) how could i find the y whitch is ED in this firgure.

heres the picture.
I'm not seeing the picture. Maybe it's just my proxy server blocking stuff. I suggest you post this question in a separate thread so others can respond as well.