If r1 = r + r2 + r3 then prove that the triangle is a right angled triangle. Share with your friends Share 9 Brijendra Pal answered this Dear Student, Dear Student, Dear Student, r1=r+r2+r3△s-a=△s+△s-b+△s-c1s-a-1s=1s-b+1s-cass-a= 2s-b-cs-bs-cass-a= a+b+c-b-cs-bs-c1ss-a=1s-bs-cs2-sb+c+bc= s2-assa-b-c+bc=0 a+b+c2a-b-c= -bca2-b+c2= -2bca2-b2-c2-2bc=-2bca2= b2+c2So it is a right angle triangle Regards 41 View Full Answer Bharath Jawahar answered this Me too having same doubt -21