standard_description: Derive the formula A = 1/2 ab sin(C) for the area of a triangle by drawing an auxiliary line from a vertex perpendicular to the opposite side.
problem_activity: Problem 1
The circumference of a circle is
$$32\pi$$
cm. What expression represents the exact area of the circle? If needed, draw a diagram to assist you.
Problem 2
Find the area and perimeter of the colored part of each figure below. The figures are composed of small squares with side length 1 unit and curves that are an arc of a circle.
a.
[IMG]
b.
[IMG]
Problem 3
A semi-circle with a diameter of 6 cm sits on top of an isosceles trapezoid. Find the area of the entire figure.
[IMG]


aligns: no