## Princess07 3 years ago In this plan, segments AB, EF, GH, and JK are perpendicular to base BC. The instructions call for extra pieces of wood to reinforce AE, EG, GJ, and JC. Given AE = 42.2 cm, find EG to the nearest tenth of a centimeter. 42.2 cm , 40.1 cm , 36.6 cm , or 36.9 cm ??

1. Princess07

In this plan, segments AB, EF, GH, and JK are perpendicular to base BC. The instructions call for extra pieces of wood to reinforce AE, EG, GJ, and JC. Given AE = 42.2 cm, find EG to the nearest tenth of a centimeter. 42.2 cm , 40.1 cm , 36.6 cm , or 36.9 cm ??

2. henkjan

Use pythagoras, find AC (158 cm) use the similarity of the triangles => BC/FC = AC/EC find that EC is about 116 cm Same trick GC => GC is 73.7 cm 116-73.7 = EG

3. Princess07

So what would be the answer Henkjan? I tried it and I'm confused.

4. henkjan

I'd go with 42.2

5. Princess07

thats why I was just going to say.

6. henkjan

You can also do it the easier way: |BC|/|FH| = |AC|/|EG|

7. Princess07

This is what I came up with 42.41

8. henkjan

I got 42.16 if I calculate it at once

9. Princess07

Alright thanks, I'm going to stick with 42.2 as the answer then. : )

10. phi

|dw:1324418020350:dw|

11. phi

triangle R is congruent to triangle S. Both have equal bases (40 cm in your case), with corresponding angles that are equal. So all 3 sides of triangle R = those of S. In particular, if side AE= 42.2, then side EG= 42.2