Warm-upwith 4.3 Notes on Triangle Inequalities

1) Using your ruler and protractor try to draw an isosceles triangle.

2)Mark the congruent sides and angles.

3) Construct medians on the congruent sides.

4) Label the point where the medians intersect as Point P.

Student of the day!Block 4

Student of the day!Block 5

Student of the day!Block 6

Answers to Geometry H.W. pg. 151 #1,2 and 4

Answers to pg. 208 – 209 #2-14 all #s

Remaining H.W. Answers

Problem #10

Problem # 11

3.3 Constructing Perpendicular Lineswith 4.3 Notes on Triangle Inequalities

Construct a perpendicular line through point P to line AB.

Notice your perpendicular line. C-7 The shortest distance from a point to a line is along the _____from the point to the line.

Constructing an altitude on a triangle.

4.4 Triangle InequalitiesUse your ruler to draw a triangle with side lengths of 3 cm,4 cm and 5 cm.

Measure the angles across the sides. Do you notice therelationship between the side lengths and the anglemeasures across from them?

Triangle Inequality Conjecture

Now use your rule to create a triangle that has side lengths

3cm, 4cm and 7cm.

Can you create a triangle with 2cm, 3 cm, and 5 cm?

External Angle Conjecture

C-20 Triangle Inequality Conjecture – The sum of the lengths of any two sides of a triangle is ____________ the length of the third side.

More Conjectures

C-21 Side-Angle Inequality Conjecture – In a triangle, if

one side is longer than another side, than the angle

opposite the longer side is _____________.

C-22 Triangle Exterior Angle Conjecture – The measure of

the exterior angle of a triangle ___________________.

Geometry Homework- 3.3 pg 156 # 1- 5- 4.3 pg 218 – 219 #1 – 10 all

Remember!!! On Thursday be prepared to have a quiz on constructions 3.1 to 3.3 and on notes 4.1 to 4.3. Look at Practice Your Skills on Keymath.com for Discovery Geometry Book.

Common Test mistakes• In your conjectures from Ch.1; you had C-4Converse of Parallel Lines Conjecture: If two lines are cut by atransversal and the corresponding, …, then the lines arecongruent.Form A: If two polygons are congruent, then they have thesame number of sides. Converse: If two polygons have the same number of sides,then they are congruent.Form B: If two lines are parallel, then they have the sameslope.Converse: If two lines have the same slope, then they areparallel.