(This is called ThalesВ theorem, which is named after an ancient Greek philosopher, Thales of Miletus. MathbitsВ gives this example for finding an inscribed angle:ДЄn angle inscribed in a semicircle is a right angle. The intercepted arc is the distance of the curve formed between the two points where the chords hit the circle. The formula for finding the inscribed angle is: So, if you have a radius of 4.5 inches:ДЄnВ inscribed angleВ is an angle formed by two chords in a circle which have a common endpoint. You can also calculate the area if a circle if you know the radius. So, if your diameter is 8.5 centimeters, as in the example in the previous slide, you would have:ДЄ = ПЂ(1/2 d)^2В (Area equals pi times one-half the diameter squared.) In this formula, 'A' stands for the area, 'd' represents the diameter, ПЂ is pi, or 3.14. The '*' is the symbol used for times or multiplication. In this formula, 'A' stands for the area, 'r' represents the radius, ПЂ is pi, or 3.14. The formulas for the area of a circle are: Think of the area of the circle as if you draw the circumference and fill in the area within the circle with paint or crayons. The area of a circle is the total area that is bounded by the circumference. Or, if you want to know the circumference of a pot that has a radius of 4.5 inches, you would have:Д¬ = 2ПЂr C = 2 * 3.14 * (4.5 in) C = 28.26 inches, which rounds to 28 inches So if youВ measure the diameter of a circle to be 8.5 cm, you would have:Д¬ = ПЂd C = 3.14 * (8.5 cm) C = 26.69 cm, which you should round up to 26.7 cm

Where d is the diameter of the circle, r is its radius, and ПЂ is pi. You can calculate the circumference of any circle if you know either the radius or diameter.

Pi is the fixed ratioВ used toВ calculate the circumference of the circle Pi, which is usually denoted with the Greek letterВ ПЂ, is the ratio of the circle's circumference to its diameter, or approximately 3.14. To measure the circumference of a circle, you need to use 'Pi,' a mathematical constant discovered by the Greek mathematician Archimedes.

The 'В°' is the mathematical symbol for degrees. The circumference of a circle is the measured total length around a circle, which when measured in degrees is equal to 360В°. It is denoted by C in math formulas and has units of distance, such as millimeters, centimeters, meters, or inches. The circumferenceВ of a circleВ is its perimeter or distance around it.

Family circle slice it up