Coordinate Geometry Level 3 Practice Quiz: Section Formula, Area and Lines
Coordinate Geometry Level 3 on Aptitude360 is an advanced practice set on points, lines and triangles in the Cartesian plane. It covers section formula ratios, centroids and midpoints, collinearity, areas of triangles and quadrilaterals, and equations of medians and perpendicular bisectors. Every question comes with a worked solution.
Topics covered in this Coordinate Geometry Level 3 set
- Distance formula, equidistant points and unknown coordinates from a given distance
- The ratio in which an axis or a given line divides a segment
- Recovering a missing vertex from the centroid or midpoints of a triangle or parallelogram
- Areas of triangles and quadrilaterals, and collinearity of three points
- Slopes of parallel and perpendicular lines, and the angle a line makes with the x-axis
- Line equations from intercepts, medians, perpendicular bisectors and intersecting lines
- Reflections in the axes and the origin, and the circumradius of a triangle
Key coordinate geometry formulas to remember
- Distance: \( d=\sqrt{(x_{2}-x_{1})^{2}+(y_{2}-y_{1})^{2}} \)
- Section formula, ratio m : n (y likewise): \( x=\dfrac{mx_{2}+nx_{1}}{m+n} \)
- Centroid x-coordinate (y likewise): \( \bar{x}=\dfrac{x_{1}+x_{2}+x_{3}}{3} \)
- Triangle area with one vertex at the origin: \( \dfrac{1}{2}\left|x_{1}y_{2}-x_{2}y_{1}\right| \)
- Slope: \( m=\dfrac{y_{2}-y_{1}}{x_{2}-x_{1}} \), where \( x_{1}\neq x_{2} \)
- Perpendicular lines, both slopes defined: \( m_{1}m_{2}=-1 \)
Revision tips for harder coordinate geometry problems
- For the ratio in which a line divides a segment, take the ratio as k to one and substitute the point of division into the line's equation.
- Test collinearity by setting the triangle area to zero, which also works when a line is vertical.
- In a parallelogram the diagonals bisect each other, so equate their midpoints to find the fourth vertex.
Who this Level 3 set is for
This set suits students who are comfortable with basic coordinate geometry and want harder multi-step practice for the quantitative aptitude sections of competitive exams.