Geo Coordinate Proofs

If two lines are parallel, what must be true about their slopes?

• The slopes are equal

• The slopes are negative reciprocals of each other

• The slopes are negatives of each other

• The slopes are reciprocals of each other

Which of the following conditions makes a parallelogram a rectangle?

• All angles are right angles

• Opposite sides are congruent

• Opposite sides are parallel

• All sides have equal length

To prove a quadrilateral is a rectangle, you can first find the ​ (a)   of all sides.

Then, look for ​ (b)   slopes, which indicate ​ (c)   lines. Perpendicular lines form ​ (d)   angles.

A quadrilateral with all right angles proves it is a rectangle.

• slope
• negative reciprocal
• perpendicular
• right
• lengths
• equal
• parallel