mathematics 7 Circles and Area
M01 Students will be expected to demonstrate an understanding of circles by
M02 Students will be expected to develop and apply a formula for determining the area of triangles, parallelograms, and circles.
SP03 Students will be expected to construct, label, and interpret circle graphs to solve problems.
 describing the relationships among radius, diameter, and circumference
 relating circumference to pi
 determining the sum of the central angles
 constructing circles with a given radius or diameter
 solving problems involving the radii, diameters, and circumferences of circles.
M02 Students will be expected to develop and apply a formula for determining the area of triangles, parallelograms, and circles.
SP03 Students will be expected to construct, label, and interpret circle graphs to solve problems.
activities

 Discovering the Area Formula for Triangles from Illuminations  In this lesson, students develop the area formula for a triangle. Students find the area of rectangles and squares, and compare them to the areas of triangles derived from the original shape.
 Geoboard Triangles from Henri Picciotto  Use an 11 by 11 geoboard to ask students to find triangles with an area of 15. After some right triangles have been found, challenge students to find some other examples.You could then ask students to "Find all the triangles that have one horizontal side, and area 15". Students who need a challenge could be asked to "Find triangles with area 15, such that none of their sides are horizontal or vertical".

 Save the Pies for Dessert from Stephen Few  Stephen Few argues that pie charts should be used sparingly, if ever. Circles graphs are sometimes used when other ways of presenting the data might be more clear.

 Circle Area Problem from Don Steward the squares have had touching circles, semicircles, quadrants
drawn inside them. Which design has the largest orange fraction (of the whole square) shaded? This question was from an article by D.B. Eperson in Mathematics in School from January 1992.