In a triangle ABC, if a=4, b=8 and `angleC=60^(@)`, then :
(where symbols used have usual meanings)

In DeltaABC, if 2b =a+ c and A-C=90^(@), then sin B equal All symbols used have usual meaning in Delta ABC.]

In DeltaABC, if 2b =a+ c and A-C=90^(@), then sin B equal All symbols used have usual meaning in Delta ABC.]

In DeltaABC, if 2b =a+ c and A-C=90^(@), then sin B equal All symbols used have usual meaning in Delta ABC.]

In a triangle ABC, if a=13,b=14 and c=15, then angle A is equal to (All symbols used have their usual meaning in a triangle.)

In DeltaABC, angleA=60^(@), angleB=90^(@), angleC=30^(@) . Let H be its orthocentre, then : (where symbols used have usual meanings)

In DeltaABC, angleA=60^(@), angleB=90^(@), angleC=30^(@) . Let H be its orthocentre, then : (where symbols used have usual meanings)

In a equilateral triangle r, R and r_(1) form (where symbols used have usual meaning)

In a triangle ABC if a, b, c are in A.P. and C-A=120^(@) , then (s)/(r )= (where notations have their usual meaning)