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PrintTeacher  Felicia Taylor 

Subject Area  Geometry Honors 

Grade Level  8th 

Week #  25 

Unit of Instruction  7: TwoDimensional Measurements 

Standard(s) Taught 

MAFS.912.GC.2.5
Derive using similarity the fact that the length of the arc intercepted by an angle is proportional to the radius.
MAFS.912.GGMD.1.1
Give an informal argument for the formulas for the circumference of a circle, area of a circle.
MAFS.912.GGPE.2.7
Use coordinates to compute perimeters of polygons and areas of triangles and rectangles, e.g., using the distance formula.

Learning Targets and Learning Criteria 

I can
 calculate the area of a circle
 define regular polygons
 inscribe a regular polygon in a circle and break it into many congruent triangles to find its area.
 explain and use the dissection method on regular polygons to generate an area formula for regular polygons.
 calculate the area of a regular polygon
 use pictures to explain that a regular polygon with many sides is nearly a circle, its perimeter is nearly the circumference of a circle, and that is apothem is nearly the radius of a circle.
 substitute the “nearly” values of a many sided regular polygon into A = 1/2* apothem * perimeter to show that the formula for the area of a circle is A = (PI) r^{2}
 use the distance formula to compute the perimeter and area given the coordinates of vertices of a polygon like triangle, square, rectangle, kite, rhombus, trapezoid, etc.
 decompose more complex figures whose vertices are given using coordinates into familiar shapes that are easier to work with.

Classroom Activities 

Monday (President’s Day)
No School
Tuesday (7th & 8th Periods)
 Instruction: Area of Parallelograms and Triangles
 Exit Ticket: Area of Parallelograms and Triangles
 Instruction: Area of Trapezoids, Rhombuses and Kites
 Exit Ticket: Area of Trapezoids, Rhombuses and Kites
 Instruction: Area of Regular Polygons
 Exit Ticket: Area of Regular Polygons
Wednesday (All Classes – 40 minutes each)
 Review
 kahoot! – Area of Parallelograms and Triangles (All classes)
 kahoot! – Area of Trapezoids, Rhombuses and Kites (7th & 8th periods only)
 kahoot! – Area of Regular Polygons (7th & 8th Periods only)
Thursday (2nd Period)
 Bellringer – Area of Parallelograms and Kites
 Instruction – Area of Trapezoids, Rhombuses and Kites
 Exit Ticket – Area of Trapezoids, Rhombuses and Kites
 Instruction – Area of Regular Polygons
 Exit Ticket – Area of Regular Polygons
 Instruction – Perimeters and Areas of Similar Figures
 Exit Ticket – Perimeters and Areas of Similar Figures
Friday (7th & 8th Periods)
 Review
 kahoot
 Areas of Parallelograms and Triangles
 Areas of Trapezoids, Rhombuses and Kites
 Areas of Regular Polygons
 Bellringers
 Areas of Parallelograms and Triangles
 Areas of Trapezoids, Rhombuses and Kites
 Areas of Regular Polygons
 Instruction – Perimeters and Areas of Similar Figures
 Exit Ticket – Perimeters and Areas of Similar Figures
 Instruction – Trigonometry and Area
 Exit Ticket – Trigonometry and Area

Assignments Due 

Summatives
None
Formatives
None

Additional Resources 

Nearpod Notes:
 Areas of Parallelograms and Triangles – Nearpod CODE: XWPEH
 Areas of Trapezoids, Rhombuses and Kites – Nearpod CODE: CEAKY
 Areas of Regular Polygons – Nearpod CODE: NHKEI
 Perimeters and Areas of Similar Figures – Nearpod CODE: BLFSN
 Trigonometry and Area – Nearpod CODE: GJXTS
Nearpod Exit Tickets:
 Areas of Parallelograms and Triangles – Nearpod CODE: TVYPQ
 Area of Trapezoids, Rhombuses and Kites – Nearpod CODE: VAMCT
 Areas of Regular Polygons – Nearpod CODE: NIADL
 Perimeters and Areas of Similar Figures – Nearpod CODE: YHASK
 Trigonometry and Area – Nearpod CODE: FYRIJ
Nearpod Bellringers:
 Areas of Parallelograms and Triangles – Nearpod CODE: OJFLM
 Areas of Trapezoids, Rhombuses and Kites – Nearpod CODE: IYVHZ
 Area of Regular Polygons – Nearpod CODE: HRPLZ
 Perimeters and Areas of Similar Figures – Nearpod CODE: TKZAS
 Trigonometry and Area – Nearpod CODE: MEWNY
Also see the following videos in Geometry Nation, for more help:
 Section 6, Topic 3: Area and Perimeter in the Coordinate Plane – Part 1
 Section 6, Topic 4: Area and Perimeter in the Coordinate Plane – Part 2
 Section 11, Topic 6: Area of ngons
 Section 12, Topic 1: Circumference of a Circle
 Section 12, Topic 2: Area and Circumference of a Circle
 Section 12, Topic 3: Area of a Circle
 Section 12, Topic 4: Sectors of a Circle
 Section 14, Topic 9: Areas in RealWorld Contexts
In addition, www.khanacademy.com is always a good help!
