## Lecture-6

00:01:20 NCERT Exercise 6.3 Question 1 State which pairs of triangles in Fig. 6.34 are similar. Write the similarity criterion used by you for answering the question and also write the pairs of similar triangles in the symbolic form :

00:15:20 NCERT Exercise 6.3 Question 2 In Fig. 6.35, ∆ ODC ~ ∆ OBA, ∠ BOC = 125° and ∠ CDO = 70°. Find ∠ DOC, ∠ DCO and ∠ OAB.

00:22:10 NCERT Exercise 6.3 Question 3 Diagonals AC and BD of a trapezium ABCD with AB || DC intersect each other at the point O. Using a similarity criterion for two triangles, show that OA/OB=OC/OD

00:29:20 NCERT Exercise 6.3 Question 4 In Fig. 6.36, QR/QT=QS/PR and ∠ 1 = ∠ 2. Show that ∆ PQS ~ ∆ TQR.

00:34:50 NCERT Exercise 6.3 Question 5 S and T are points on sides PR and QR of ∆ PQR such that ∠ P = ∠ RTS. Show that ∆ RPQ ~ ∆ RTS.

00:38:10 NCERT Exercise 6.3 Question 6 In Fig. 6.37, if ∆ ABE ≅ ∆ ACD, show that ∆ ADE ~ ∆ ABC.

00:45:00 NCERT Exercise 6.3 Question 7 In Fig. 6.38, altitudes AD and CE of ∆ ABC intersect each other at the point P. Show that: (i) ∆ AEP ~ ∆ CDP (ii) ∆ ABD ~ ∆ CBE (iii) ∆ AEP ~ ∆ ADB (iv) ∆ PDC ~ ∆ BEC

00:53:50 NCERT Exercise 6.3 Question 8 E is a point on the side AD produced of a parallelogram ABCD and BE intersects CD at F. Show that ∆ ABE ~ ∆ CFB.

00:57:50 NCERT Exercise 6.3 Question 9 In Fig. 6.39, ABC and AMP are two right triangles, right angled at B and M respectively. Prove that: (i) ∆ ABC ~ ∆ AMP (ii) CA/BC=PA/MP