If p = 106, q = 105 and r = 104, then value of p2 + q2 + r2 - pq - qr - rp is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 3.
p2 + q2 + r2 - pq - qr - rp = (1/2)[(p - q)2 + (q - r)2 + (r - p)2]
= (1/2)[(106 - 105)2 + (105 - 104)2 + (104 - 106)2]
= (1/2)[(1)2 + (1)2 + (-2)2]
= (1/2) × 6
= 3