MathRevolution
[GMAT math practice question]
Attachment:
1.13PS.png
The figure shows that \(OABC\) is a parallelogram. What is the equation of the line passing through \(A\) and \(C\)?
A. \(y = \frac{1}{10}x + \frac{3}{10}\)
B. \(y = \frac{5}{11}x + \frac{20}{11} \)
C. \(y = \frac{5}{12}x + \frac{3}{12 }\)
D. \(y = \frac{1}{13}x + \frac{3}{13}\)
E. \(y = \frac{5}{14}x + \frac{3}{14}\)
Let C = (a, 0)
Given A = (7, 5), B = (3, 5) & O = (0, 0)
Note that, Length of AB & OC are same
--> \(\sqrt{(3 - 7)^2 + (5 - 5)^2} = \sqrt{(a - 0)^2 + (0 - 0)^2}\)
--> \(\sqrt{16 + 0} = \sqrt{a^2}\)
--> \(a = -4\) [As "a" lies on the negative x-axis!]
--> Point C = (-4, 0)
Alternate method to find C: Note that point B is 4 units to the left of point A. So, Point C will also be 4 units to the left of O.
--> C = (-4, 0)Slope of the line passing through A & C = \(\frac{0 - 5}{-4 - 7} = \frac{5}{11}\)
Only option B has slope = \(\frac{5}{11}\)
Option B