KVPY2015MathematicsStraight Lines
Let ABCD be a square of a side length 1 , Let P , Q , R , S be points in the interiors of the sides A D, B C, A B, C D , respectively, such that P Q and RS intersect at right angles. If P Q= 3 3 4 then RS equals
Options
- A2 3
- B3 3 4
- C2 +1 2
- D4-2 2
Correct answer
B. 3 3 4
Step-by-step solution
PQ RS c-a=b-d array l P Q= 3 3 4 P Q²= 27 16 1+(a-c)²= 27 16 R S= (b-d)²+1 array By equation (1),(2) and (3) R S= 3 3 4