Question: Slope formula

Answer: Slope= y2-y1/x2-x1

Question: Determine the product to find out if the triangle is A right angle

Answer: Multiply the slopes

If any of the products are -1, you can stop checking the other products

Since a triangle can only have 1 right angle, one occurrence if -1 implies that the triangle is a right triangle

Question: Determining if a quadrilateral is a parallelogram using the parallel lines theorem

Answer: The theorem states that 2 coplanar nonvertical Linda are parallel if and only if they have the same slope

So determine the slopes of each of the sides of the quadrilateral and if the opposite sides have the same slope, the quadrilateral IS a parallelogram

Question: Determining if a quadrilateral is a rectangle

Answer: You must first show that the quadrilateral is a parallelogram and then show that is has 4 right angles

Question: Determining if a quadrilateral is a rhombus

Answer: You must first show that the quadrilateral is a parallelogram and then use the distance formula to show that it has 4 congruent sides

Question: Determining if a quadrilateral is a trapezoid

Answer: You must show that one pair of the opposite sides are parallel and that the other pair of opposite sides are NOT parallel