Do the exercises on your paper and be collected 20 May 2010

1. A cube ABCD.EFGH with length of edge is 4 cm. Evaluate the length of projection edge CG at plane BDG!

2. A cube ABCD.EFGH with length of edge is 5 cm. Evaluate the length of projection edge BG at plane BDHF!

3.  A regular four plane pyramid  T.ABCD, AB = 6 cm, TA = 8 cm. Evaluate the length of projection :

a. edge AB  at plane TBD

b.  edge AB  at plane TBC

4. Regular rectangular pyramid  T.ABCD, TA = 8cm, AB = 8 cm. If P midpoint AT, then find the length of projection CP to plane ABCD

5. Cube  ABCD.EFGH has length of AB = 12 cm, if P and Q midpoint BC and GH respectively  the length of projection  line  PQ to    plane BDHF