DB'Z+CB'Q=90 DZB'+DB'Z=90 DB'Z+CB'Q=DZB'+DB'Z 2)CB'Q=DZB' (these angles from two triangles ZDB' and B'CQ ) 3)so,angles DB'Z and B'QC are going to be equal because of sum of three angles in triangles =180 degrees and 2 angles already equal. so this triangles are similar by tree angles b) B'C:B'D=3:4 B'D:DZ=3:2 CQ-? DC=AB=21 DC=B'C+B'D (3+4= 7 parts) 21/7=3 B'C=3*3=9 B'D=3*4=12 B'D:DZ=3:2 12:DZ=3:2 DZ=12*2/3=8 B'D:DZ=CQ:B'C 3:2=CQ:9 CQ=3*9/2=27/2
c) BC=BQ+QC=B'Q+QC BQ' can be found by pythagorean theorem