SA3 marksYear: 2023HardCBSE Class 10
trianglessimilarityperpendicular-bisectorproof
Question
In the given figure, CD is the perpendicular bisector of AB. EF is perpendicular to CD. AE intersects CD at G. Prove that CDCF=DGFG.
Solution
1
△EFG∼△ADG (AA similarity)
⇒ADEF=DGFG ... (i)
+1 mark2
△EFC∼△BDC (AA similarity)
⇒BDEF=CDCF
+1 mark3
⇒ADEF=CDCF {since BD=AD} ... (ii)
+0.5 marks4
Using (i) and (ii): DGFG=CDCF
+0.5 marks