Geometry, Part 8
Question 1: Tell how to find the area, circumference, and diameter of a circle.
Answer 1: The area of a circle is found by the formula ?=?2, where A is the area and r is the length of the radius. If the diameter of the circle is given, remember to divide it in half to get the length of the radius before proceeding.The circumference of a circle is found by the formula ?=2?, where C is the circumference and r is the radius. Again, remember to convert the diameter if you are given that measure rather than the radius.To find the diameter when you are given the radius, double the length of the radius.
There are lots of good resources about Geometry that you can find available.
Question 2: Tell how to find the area and perimeter of a trapezoid.
Answer 2: The area of a trapezoid is found by the formula ?=12h(?1+?2), where A is the area, h is the height (segment joining and perpendicular to the parallel bases), and b1 and b2 are the two parallel sides (bases). Do not use one of the other two sides as the height unless that side is also perpendicular to the parallel bases.The perimeter of a trapezoid is found by the formula ?=?+?1+?+?2, where P is the perimeter, and a, b1, c, and b2 are the four sides of the trapezoid. Notice that the height does not appear in this formula.
Question 3: Tell how to find the lateral surface area and volume of a sphere.
Answer 3: The lateral surface area is the area around the outside of the sphere. The lateral surface area is given by the formula ?=4?2, where r is the radius. The answer is generally given in terms of pi. A sphere does not have separate formulas for lateral surface area and total surface area as other solid figures do. Often, a problem may ask for the surface area of a sphere. Use the above formula for all problems involving the surface area of a sphere.The volume is given by the formula ?=43?3, where r is the radius.
Previous: Geometry, Part 7 - Next: Georgia Assessments for the Certification of Educators, Part 1
|
