Coordinate Plane Triangles

Find the perimeter of this triangle.

• 150 ft

• 100 ft

• 20 ft

• 35 ft

Given that A(-2,3), B(4,1) and C(2,-4) are vertices of a triangle, find the perimeter of the triangle.

• 20.789

• 19.772

• 23.9

• 13.456

Points G, H, and I are plotted on the coordinate grid. What is the perimeter (in units) of the triangle that they form?

• 16.64

• 39.64

• 126

• 63

If a triangle with vertices of (-3,0), (0,3), (3,0), classify it by its sides.

• Isosceles

• Scalene

• Equilateral

• Obtuse

Given that P(-4, -2), Q(-2, 2) and R(5, 1) are vertices of a triangle, calculate the perimeter and classify the triangle.

• 21.1, Isosceles

• 21.1, Scalene

• 24.3, Scalene

• 24.3, Equilateral

Calculate the length for each side of the triangle.

• AB = 3.6, BC = 4.5, AC = 4.1

• AB = 4.1, BC = 5.6, AC = 7.5

• AB = 4.5, BC = 3.6, AC = 4.1

• AB = 4.1, BC = 3.6, AC = 4.5

Find the area?

• 15 in²

• 30 in²

• 15 in

•  30 in

Explain why it is convenient to place a right triangle on the grid as shown when writing a coordinate proof.

• The hypotenuse of the right triangle is easy to identify.

• The side lengths are often easier to find because you are using zeros in your expressions.

• It is easier to dilate the figure on the coordinate plane.

• Both legs have the same length when you place the triangle on the x- and y-axes.

Write a plan for the proof. Given Coordinates of vertices of △OPM and △ONM Prove △OPM and △ONM are isosceles triangles

• Find the lengths of OP, PM, MN, NO and OM to show that △OMP≅△OMN by the SSS Congruence Theorem.

• Find the lengths of OP, PM, MN, and NO to show that OP ≅ PM and MN ≅ NO.

Write a plan for the proof.  Given: G is the midpoint of HF Prove: △GHJ≅△GFO

• Find the coordinates of G using the Midpoint Formula
  Use these coordinates and the Distance formula to show that OG ≅ JG.
  Show that HG≅ FG by the definition of midpoint and ∠HGJ ≅ ∠FGO by the Vertical Angles Congruence Theorem.
  

• Find the coordinates of G using the Distance Formula
  Use these coordinates and the Midpoint formula to show that OG ≅ JG.
  Show that HG≅ FG by the definition of midpoint and ∠HGJ ≅ ∠FGO by the Vertical Angles Congruence Theorem.

• Then, use the SAS Congruence Theorem to conclude that △GHJ ≅ △GFO.

• Then, use the SSS Congruence Theorem to conclude that △GHJ ≅ △GFO.