Download Date: THROUGH-LINE: Creation-enjoying OUTCOMES: 1

Lesson #4 title: PART 4 = IDENTIFYING triangles in the 1st quadrant of a Cartesian plane (more practice with Δ)
Date:
THROUGH-LINE: Creation-enjoying
Creation is enjoyed when SIDE lengths and/or INTERIOR  are used to classify triangles and regular & irregular polygons.
OUTCOMES:
1. Identify the characteristics of a given set of triangles according to their sides and/or their
interior angles (e.g., SIDES = equilateral Δ, isosceles Δ, scalene Δ; INTERIOR  = acute Δ, right Δ, obtuse Δ)
MATERIAL NEEDED: highlighters, pencil, blue pen, double scale protractor, ruler
Example #1: (obtained from Quest2000 p.221; MF6 p.268)
Can a triangle have each of these angles? Draw a sketch or a diagram and/do the math calculations to
prove your answer.
a)Two obtuse interior angles and one acute angle
YES or NO because
b)An obtuse angle, a right angle, an acute angle
YES or NO because
Example #2: (obtained from Math6 Pilot2010)
If the coordinates (5,4) and (13,4) are plotted on this graph, then which points labelled on the graph could
be used as a third point to create
an isosceles triangle?
a scalene triangle?
L4(2)
YOUR TURN 
Δ
#1: DRAW each
(use ruler). Label each vertex with a different alphabetical letter and measure the
side lengths (insert ‘ticks’) and label the degrees of each angle.
#2: Calculate the value of  x in each diagram.
#3: Name each Δ using its combined name. Write name beside/underneath each Δ.
L4(3)
#4: Read each statement. Decide if each statement is either TRUE or FALSE.
Draw a sketch or a diagram and/do the math calculations to help solve. DO NOT just guess!
#5: Can a triangle have each of these angles? Draw a sketch or a diagram and/do the math calculations to
prove your answer.
a) one 90o a 30o a 60o 
YES or NO because
b) one 180o angle, a 30o angle, a 90o 
YES or NO because
c) Two right interior angles and an acute angle
YES or NO because
d) Reflex angle as an interior angle
YES or NO because
e) An obtuse and two acute 
YES or NO because
L4(4)
#6: PLOT these ordered pairs.