Exploring Quadrilaterals, Diagonals, and Polygon Angles
Dive into the world of polygons and their properties, from classifying quadrilaterals to calculating angles. Discover the sums of interior angles, diagonal relationships, and patterns in polygons. Complete a mini-lab with various polygon types and checkpoints to test your knowledge.
Exploring Quadrilaterals, Diagonals, and Polygon Angles
E N D
Presentation Transcript
Quadrilaterals, Diagonals, and Angles of Polygons • A Polygon is a simple closed plane figure, having three or more line segments as sides • A Quadrilateral is any four-sided closed plane figure • A Diagonal a line segment that connects one vertex to another (but not next to it) on a polygon
Quadrilateral Angles • We know that the interior angles of a triangle add up to 180 degrees • How many degrees are in the interior angles of a quadrilateral?
Quadrilateral Angles • If we draw a diagonal from one vertex across to the opposite vertex, we see that we have formed two triangles • Therefore, the sum of two triangles will give you the measure of the interior angles of a quadrilateral • 180 + 180 = 360 degrees!
Quadrilateral Angles Checkpoint • Find the missing angle of a quadrilateral with the following measures: m 1 = 117 m 2 = 110 m 3 = 75 m 4 = 117 + 110 + 75 + x = 360 302 + x = 360 x = 58
Angles of Polygons Mini-Lab • Let’s explore this knowledge and how it relates to the angles of other polygons • Copy and complete the table below:
Angles of Polygons Mini-Lab • Draw a pentagon with diagonals from one vertex to each opposing vertex
Angles of Polygons Mini-Lab • Let’s explore this knowledge and how it relates to the angles of other polygons • Copy and complete the table below:
Angles of Polygons Mini-Lab • Draw a hexagon with diagonals from one vertex to each opposing vertex
Angles of Polygons Mini-Lab • Let’s explore this knowledge and how it relates to the angles of other polygons • Copy and complete the table below:
Angles of Polygons Mini-Lab • Draw a heptagon with diagonals from one vertex to each opposing vertex
Angles of Polygons Mini-Lab • Let’s explore this knowledge in how it relates to the angles of other polygons • Copy and complete the table below:
Angles of Polygons Mini-Lab • What patterns do you see as a result of our experiment? • The number of triangles in any polygon is always two less than the number of sides. • Therefore, if n = the number of sides of the polygon; the sum of interior angles of any polygon can be expressed as (n – 2)180!
Angles of Polygons Checkpoint • Find the sum of the measures of the interior angles of each polygon: 15-gon? 23-gon? 30-gon? (15-sided figure) (23-sided figure) (30-sided figure) 13 x 180 = 2340
Angles of Polygons Checkpoint • Find the sum of the measures of the interior angles of each polygon: 15-gon? 23-gon? 30-gon? (15-sided figure) (23-sided figure) (30-sided figure) 13 x 180 = 2340 21 x 180 = 3780
Angles of Polygons Checkpoint • Find the sum of the measures of the interior angles of each polygon: 15-gon? 23-gon? 30-gon? (15-sided figure) (23-sided figure) (30-sided figure) 13 x 180 = 2340 21 x 180 = 3780 28 x 180 = 5040
Regular Polygons • A regular polygon is one that is equilateral (all sides congruent) and equiangular (all angles congruent) • Polygons that are not regular are said to be irregular • If the formula for finding the sum of measures of interior angles of a polygon is (n-2)180, how would you find the measure of each angle of a regular polygon? ( n – 2 )180 n
Regular Polygons Checkpoint • Find the sum of the measures of the interior angles of each regular polygon and the measure of each individual angle: 15-gon? 23-gon? 30-gon? (15-sided figure) (23-sided figure) (30-sided figure) 13 x 180 = 2340 2340 / 15 = 156
Regular Polygons Checkpoint • Find the sum of the measures of the interior angles of each regular polygon and the measure of each individual angle: 15-gon? 23-gon? 30-gon? (15-sided figure) (23-sided figure) (30-sided figure) 13 x 180 = 2340 2340 / 15 = 156 21 x 180 = 3780 3780 / 23 = 164.35
Regular Polygons Checkpoint • Find the sum of the measures of the interior angles of each regular polygon and the measure of each individual angle: 15-gon? 23-gon? 30-gon? (15-sided figure) (23-sided figure) (30-sided figure) 13 x 180 = 2340 2340 / 15 = 156 21 x 180 = 3780 3780 / 23 = 164.35 28 x 180 = 5040 5040 / 30 = 168
Homework • Skill 4: Polygons (both sides) • 6-3 Skills Practice: Polygons and Angles • DUE TOMORROW!