Question

If the vertices of a triangle are (a, 1), (b, 3) and (4, c), then the centroid of the triangle will lie on the x-axis, if

• A. a + c = -4
• B. a + b = -4
• C. c = -4
• D. b + c = -4

Answer 1

The correct option is C

c = -4

The point lies on the x-axis if its y coordinate = 0.

Y-coordinate of the centroid is $\frac{y_1+y_2+y_3}{3}=\frac{1+c+3}{3}$

Therefore, $\frac{1+3+c}{3}$ = 0 $\Rightarrow$ c = -4.