Exercise 7.1

myCBSEguide.com myCBSEguide.com Download myCBSEguide mobile app for FREE sample papers, last year papers, NCERT solutions, test papers, online tests, practice papers and many more features. Install App Now NCERT Solutions class-9 Maths Exercise 7.1 1 year agoAdd Commentby myCBSEguide2 Views FacebookTwitterGoogle+PinterestWhatsApp 1. In quadrilateral ABCD (See figure). AC = AD and AB bisects A. Show that ABC ABD. What can you say about BC and BD? Ans. Given: In quadrilateral ABCD, AC = AD and AB bisects A. To prove: ABC ABD Proof: In ABC and ABD, AC = AD [Given] BAC = BAD [ AB bisects A] AB = AB [Common] ABC ABD [By SAS congruency] Thus BC = BD [By C.P.C.T.] 2. ABCD is a quadrilateral in which AD = BC and DAB = CBA. (See figure). Prove that: (i) ABD BAC (ii) BD = AC (iii) ABD = BAC Ans. (i) In ABC and ABD, BC = AD [Given] DAB = CBA [Given] AB = AB [Common] ABC ABD [By SAS congruency] Thus AC = BD [By C.P.C.T.] (ii) Since ABC ABD AC = BD [By C.P.C.T.] (iii) Since ABC ABD ABD = BAC [By C.P.C.T.] 3. AD and BC are equal perpendiculars to a line segment AB. Show that CD bisects AB (See figure) Ans. In BOC and AOD, OBC = OAD = [Given] BOC = AOD [Vertically Opposite angles] BC = AD [Given] BOC AOD [By ASA congruency] OB = OA and OC = OD [By C.P.C.T.] 4. and are two parallel lines intersected by another pair of parallel lines and (See figure). Show that ABC CDA. Ans. AC being a transversal. [Given] Therefore DAC = ACB [Alternate an