In a triangle the lengths of two larger sides are 10 and 9 respectively.if the angles are in AP,then the length of third side can be:1.√91
2.3√3
3.5
4.none
my query:
sir this is a jee-87 question.i found the solution in arihant said the answer is √91 what they did was using cosine rule and assuming the angle opposite to third side be 60°.but i don't find it correct!
infact we are given the lengths of larger sides so logically i think that the angle opposite to third side is 60-common difference!
so applying sine rule we can find alpha first and then the length of third side!
and it turns out that answer is none of these!
plz tell if i m wrong!
1Certainly , the third side , which must be the smallest one , cannot have " 60 ° " as the opposite angle since , that would imply that the sum of the angles of a triangle is greater than " 180 ° " ( ? ) .
So , the Arihant solution is , I think , wrong .
1thanks for your response ricky ...spot on argument..in lesser words than me[3][3]...waise if u have access to 1987 questions plz try to find if there is some error in the question i typed...maybe!
thank you!