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Distance between two point `(8, -4)` and `(0, a)` is `10`. All the values are in the same unit of length. Find the positive value of a. |
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Answer» Correct Answer - 2 Let P(8, -4) and Q(0, a) be two points, distance PQ is 10. `therefore " "` According to distance formula PQ = `sqrt((x_2-x_1)^(2) + (y_2-y_1)^(2))` `" "=sqrt((0-8)^(2) + (a+4)^(2))` `rArr PQ= sqrt (64+ (a^(2) + 16 + 8a)) ` `rArr a^(2) + 8a + 80 = 100 rArr a^(2) + 8a =20` `rArr a^(2) + 10 a -2a -20=0` `rArr (a-2)(a+ 10)=0 rArr (a=2) and (a=-10)` `therfore " "a=2` |
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