Let the line x + y = 1 meet the axes of x and y at A and B, respectively. A right angled triangle AMN is inscribed in the triangle OAB, where O is the origin and the points M and N lie on the lines OB and AB, respectively. If the area of the triangle AMN is 49 of the area of the triangle OAB and AN : NB = : 1, then the sum of all possible value(s) of is:
- 12
- 52
- 2
- 136
Answer
(3) 2
Solution
[figure]
OA=OB=1, A=45 ; area AMN= 49 12= 29; right angle at N, MAN=
AM= 2 + ⇒ area = 12AM2 = 1+2 = 29
⇒ = 25 ⇒ 2 2 -5 +2=0 ⇒ = 12 (M on OB needs 45 )
AN= 21+ = 2 23, NB= 23
∴ =2
Answer: (3)