4.1 & 4.2 A Notes
Type of ∆DefinitionPicture Equilateral Triangle CLASSIFICATION BY SIDES All sides are
Type of ∆DefinitionPicture Isosceles Triangle CLASSIFICATION BY SIDES At least 2 sides base leg
Type of ∆DefinitionPicture Scalene Triangle CLASSIFICATION BY SIDES No sides are
Type of ∆DefinitionPicture Equiangular Triangle CLASSIFICATION BY ANGLES All angles are
Type of ∆DefinitionPicture Acute Triangle CLASSIFICATION BY ANGLES All angles are acute
Type of ∆DefinitionPicture Right Triangle CLASSIFICATION BY ANGLES One right angle leg hypotenuse
Type of ∆DefinitionPicture Obtuse Triangle CLASSIFICATION BY ANGLES One obtuse angle and 2 acute angles
Interior Angles –Angles inside a shape Exterior Angles –Angles outside a shape Corollary – Statement easily proved from another statement
a c b a c b The sum of the measures of a triangle = _______ 180°
If two triangles have two angles that are _______, then the third angle is also ___________. A B CD E F 40° 60° 80°
The measure of an exterior angle of a triangle is equal to the sum of the measures of the two remote interior angles. a + b = 180° b + c + d = 180° b + c + d = a + b c + d = a
The acute angles of a right triangle are ______________. complementary a c a + c + 90 = 180° a + c = 90°
Classify the triangle by its sides and angles. scalene right
Classify the triangle by its sides and angles. equilateral equiangular
Classify the triangle by its sides and angles. isosceles obtuse
4. Find the value of x. Then classify the triangle by its angles. 2x + 3x + 55 = 180 5x + 55 = x = 125 x = 25° 5 50° 75° acute
4. Find the value of x. Then classify the triangle by its angles. 4x – 5 + 3x = 180 7x + 40 = x = 140 x = 20° 7 75° 65° acute
4. Find the value of x. Then classify the triangle by its angles. 2x x x + 1 = 180 7x + 5 = x = 175 x = 25° 7 52° 76° acute
5. Find the measure of each exterior angle shown. x + 80 = 3x – 22 -x -x. 102 = 2x 51° = x 2 80 = 2x – (51) – 22 = 131°
5. Find the measure of each exterior angle shown. 2x – x = 6x – 7 -x -x. 110 = 5x 22° = x = 5x – x = 6x – 7 6(22) – 7 = 125°
5. Find the measure of each exterior angle shown. 2x = 4x x -2x. 46 = 2x 23° = x 54 = 2x + 8 2x + 54 = 4x + 8 4(23) + 8 = 100°
6. Solve for the variables. 65° y = 180 y = 25° 25° y = 180
6. Solve for the variables. 55° 5y = 180 5y = y = 55 y = 11° 5
7. Find the measure of each missing angle. 120° 60° 30° 60° 30°
Ans: **Project due Tomorrow! Bring your compass and ruler tomorrow! HW Problem SectionPage #Assignment Spiral ?s a , 14-18, 21-26, 32, 33, 35 15, # 26