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4.1 Warm up. 1. Using deductive reasoning prove the following: 4x -6 = 2(x + 9) 2) 6, 17, 28, 39….. Find the function rule and the 50th term
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4.1 Warm up 1. Using deductive reasoning prove the following: 4x -6 = 2(x + 9) 2) 6, 17, 28, 39….. Find the function rule and the 50th term 3) With parallel lines, certain relationship exist for the type of angles formed. List the type of angles that are created and their relationship.
Answers • 4x-6 = 2(x+9) Given • 4x-6 = 2x + 18 Distributive Prop • 2x – 6 = 18 Subtraction prop. of equality • 2x = 24 Addition prop. of equality • x = 12 Division prop. of equality • 6, 17, 28, 39…… nth term = f(n) = 11n – 5 50th term = 545 • Vertical angles, corresponding angles, alt. exterior, alt interior are congruent • Same side interior, same side exterior, linear pairs add to 180
Triangles- Come in 3 types: Obtuse: Right: Acute: An acute triangle has 3 acute angles An obtuse triangle has 1 obtuse angle A right triangle has 1 right angle. • Sub groups • Scalene Triangle nocongruent sides. • Equilateral Triangle all sides are congruent. • Isosceles Triangle at least 2congruent sides. You can have Scalene and Isosceles of each type of triangle!
Triangles Sketch each type of triangle in the box
Ex. 1 - Triangles • How do I sketch, label, and mark each figure? • A) Right Isosceles triangle SUN with SU = UN. • B) Obtuse Isosceles triangle SEA with SE = EA.
Triangles class work! Page 64-65 Questions #2-20 More to come……stay tuned!
4.1 Triangle Congruence Year 2 Geometry
Materials • You will need: • Protractor • Scissors
Investigation #1 • Draw a triangle using your straight edge of the protractor. Make a variety of sizes! • Measure each angle of the triangle to the nearest 10°. The sum of the interior angles equals to ? • Cut out the triangle (around the perimeter). • Cut 2 of the vertices (angles) from the triangle. • Line up all three vertices. What do you notice? 180° They form a line. (180°)
Investigation #1 – continued • Paste the three vertices lined up in your notes and complete the following conjecture. Triangle Sum Conjecture The sum of the measures of the interior angles in every triangle is _______. 180°
Third Angle Conjecture If two angles of one triangle are equal in measure to two angles in another triangle, then the third angle in each triangle is ___________________________? equal in measure
Example#1 x 52° 55°
Example #2 z x 130° 50° 100° 60° 120°
Example #3 B x+7 2x-9 x C A
w 48° Example #4 x x
Example #5 B 4x+25 3x+13 2x+7 A C
Example 6 • With a partner create your own problem with triangles similar to the previous examples to share with your group.
Summary • Write the Triangle Sum Conjecture in your own words.
In – Class Work • Lesson 4.1 – workbook • Homework: Triangle Sum HW pg 201-202 2-5,8,9, 14-16