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3.6 Angles in Polygons. Date: _________. Sums of Interior Angles. Triangle. Quadrilateral. Pentagon. = 2 triangles. = 3 triangles. Hexagon. Octagon. Heptagon. = 4 triangles. = 5 triangles. = 6 triangles. 3. 1. 180 . 4. 360 . 2. 540 . 5. 3. 720 . 6. 4. 900 . 5. 7.
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3.6Angles in Polygons Date: _________
Sums of Interior Angles Triangle Quadrilateral Pentagon = 2 triangles = 3 triangles Hexagon Octagon Heptagon = 4 triangles = 5 triangles = 6 triangles
3 1 180 4 360 2 540 5 3 720 6 4 900 5 7 8 6 1080 n n – 2 180•(n – 2)
135 100 70 x Find the measure of the missing angle in the figure below 135 + 100 + 70 + x = 360 305 + x = 360 -305 -305 x = 55 quadrilateral
(4x + 15) 2 (5x - 5) (8x - 10) 1 3 110 Find m1. 5(20) - 5 m1 = = 95 5x - 5 + 4x + 15 + 8x - 10 + 110 + 90 = 540 17x + 200= 540 pentagon -200 -200 17x = 340 17 17 x = 20
2 1 3 5 6 4 Interior Angles Exterior Angles
2 1 3 5 6 4 Sums of Exterior Angles 180 180 180•3 = 540 180 Sum of Interior & Exterior Angles = 540 Sum of Interior Angles = 180 360 540- 180= Sum of Exterior Angles =
Sums of Exterior Angles 180 180 180 180•4 = 720 180 Sum of Interior & Exterior Angles = 720 Sum of Interior Angles = 360 360 720- 360= Sum of Exterior Angles =
Sum of Exterior Angles 180 180 180 180 180 180•5 = 900 900 Sum of Interior & Exterior Angles = Sum of Interior Angles = 540° 360 900- 540= Sum of Exterior Angles =
Sum of Exterior Angles 180 180 180 180 180 180 180•6 = 1080 1080 Sum of Interior & Exterior Angles = Sum of Interior Angles = 720° 1080- 720= Sum of Exterior Angles = 360
Sums of Exterior Angles 540 180 360 720 360 360 900 540 360 1080 720 360 Sum of Exterior Angles is always 360!
Angles of Regular Polygons Sum of the Interior Angles 180(n – 2) Sum of the Exterior Angles Always 360! 180(n – 2) Each Interior Angle n Each Exterior Angle 360 n
Find the sum of the measures of the interior angles of a regular dodecagon. n = 12 180•(n – 2) = 180•(12 – 2) = 180•(10) all 12 angles = 1800 What is the measure of each angle? 1800 each angle = 150 12
The sum of the interior angles of a convex polygon is 1440. How many sides does the polygon have? 180•(n – 2) = 1440 180n – 360 = 1440 + 360 +360 180n = 1800 180 180 n = 10 10 sides
Exterior Angles What is the measure of each exterior angle of a regular hexagon? 6 sides 360 = 60 6
The measure of each exterior angle of a regular polygon is 20. How many sides does it have? 360 = 18 20 The measure of each interior angle of a regular polygon is 120. How many sides does it have? 180 - 120 60 = 360 = 6 60 exterior angle
Find the sum of the interior angles of a 100-gon! Find the sum of the exterior angles of a 100-gon. Find the measure of each interior angle of a 100-gon. Find the measure of each exterior angle of a 100-gon.