# This arc length and area of a sector lesson can be used to calculate calorie percentages in food portions like pizza slices

Subjects:

Computers & Internet, Math, P.E. & Health

10, 11, 12

Title – Area of Polygons, Arc Length and Area Sectors
By – Gabriela Pena
Primary Subject – Math
Secondary Subjects – Computers & Internet, PE & Health
Grade Level – 10-12

Concept / Topic To Teach:

Measurement

Texas Essential Knowledge and Skills Standards for Mathematics:

111.34.b Geometry

(G8) Congruence and the geometry of size. The student uses tools to determine measurements of geometric figures and extends measurement concepts to find perimeter, area, and volume in problem situations. The student is expected to:

(A) find areas of regular polygons, circles, and composite figures;

(B) find areas of sectors and arc lengths of circles using proportional reasoning

General Goal(s):

The students will be able to demonstrate an understanding of the concepts and uses of measurements in composite figures and the arc length and area sector of a circle.

• Find the area of the square cardboard
• Find the area of the circle
• Find the area of a sector and arc length

Specific Objectives:

1. Given a cardboard cutout square, the students will have to decide the dimensions of the biggest circle that could be cut out from the square.
2. Determine the difference between the area of the square and the circle.
3. The students will then have to decide to divide the circle into 8, 10, or 12 sections.
4. The students will find the arc length and area sector of a certain section.

Required Materials:

• calculator
• pencil
• color pencils
• markers
• paper
• formula chart
• ruler
• cardboard
• scissors
• camera
• computer
• Photo Story 3