I put what I think each of these are but I only think that I got a few of them right.

RainbowPanda Feb 27, 2018

#1**+1 **

15...if these are similar....we must have that

13/15 = 30/35

13/15 = 6/7 not true....so these are not similar

16.....if these were similar.....we must have that

40/60 = 23/34

2/3 = 23/34 ....not true.....so.....not similar

17 For these to be similar...we must have that

16/22 = 25 /33

8/11 = 26/33 .....not true....not similar

18 EFG similar to EBC

Angle E = Angle E and

EF / EG = EB/EC

50/60 = 20/24

5/6 = 5/6

19 Not similar

20 Not similar

CPhill Feb 27, 2018

#3**+2 **

One way for triangles to be similar is that we need that the ratios of the corresponding sides to be =

That is

short side of first triangle

_____________________ = A

short side of second triangle

Intermediate side of first triangle

__________________________ = B

Intermediate side of second triangle

Long side of first triangle

_______________________ = C

Long side of second triangle

So A = B = C for the triangles to be similar

So.....For 16 to be similar...we need that

23/40 = 34/55 = 36/60

23/40 = 34/55 = 3/5

None of these ratios are equal...so....not similar

For 17 to be similar....we need the sides around the equal angle need to be equal ratios

But

16/22 = 25/33 ???

8/11 = 25/33 these are not equal

For the same reason....the triangles in 19 aren't similar, either

In other words 14/9 not equal to 7/4

And the triangles in 20 are not similar because we can't establish any AA similarity

CPhill Feb 27, 2018