alleryStart learning →Distance between two points (x1, y1) and (x2, y2) is given by
A(x1 + y1)(x2 + y2) overall
B(x2 - x1) + (y2 - y1) directly
Csqrt(x1 * x2 + y1 * y2) only
Dsqrt((x2 - x1)^2 + (y2 - y1)^2)
Answer & Solution
Correct answer: D. sqrt((x2 - x1)^2 + (y2 - y1)^2)
1. Form a right triangle with the segment as hypotenuse.
2. Legs are |x2 - x1| and |y2 - y1|.
3. By Pythagoras the distance squared is (x2 - x1)^2 + (y2 - y1)^2.
4. So option A is correct.
_Source: Selina Concise Mathematics Class 9, Ch 26 Co-ordinate Geometry (Mistral OCR'd PDF), section on distance formula_
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