170 likes | 303 Views
Formulae. http://hench-maths.wikispaces.com. Perimeter Formulae for Polygons. Area of rectangle. Area= bh. h=height. b=base. Base is at RIGHT ANGLE to Height. Area of Square. A square is a rectangle with all equal sides Base=Height. Area= b 2. Height=Base=b. b=base.
E N D
Formulae http://hench-maths.wikispaces.com
Area of rectangle Area= bh h=height b=base Base is at RIGHT ANGLE to Height
Area of Square A square is a rectangle with all equal sides Base=Height Area= b2 Height=Base=b b=base
Area of a Parralelogram Area= bh Base is at RIGHT ANGLE to Height
Area of a triangle height height base base The area of a triangle is equal to half the area of the rectangle that can be drawn with the same base and height. The Area of the triangle can thus be calculated using the formula Area = ½ base x height or in algebraic form A= ½ bh
Examples 7cm 8cm 6cm 10cm Area =½ base X height = ½ x 10 x 8 = ½x80 =40 sq cm Area =½ base X height = ½ x 6 x 7 = ½x42 =21 sq cm
What is the formula relating the circumference to the diameter? circumference centre Diameter Radius
C = ? x d People knew that the circumference is about 3 times the diameter but they wanted to find out exactly. C ≈ 3 x d This means APPROXIMATELY EQUAL TO
How can we find the relationship between the circumference of a circle and its diameter?
Early Attempts Egyptian Scribe Ahmes. in 1650 B.C. said C≈3.16049 x d Archimedes, said C ≈3.1419 x d Fibonacci. In 1220 A.D. said C≈3.1418xd What is the value of the number that multiplies the diameter to give the circumference????
The exact value is…………… UNKNOWN!!
An approximation to π π≈3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067982148086513282306647093844609550582231725359408128481117450284102701938521105559644622948954930381964428810975665933446128475648233786783165271201909145648566923460348610454326648213393607260249141273724587006606315588174881520920962829254091715364367892590360011330530548820466521384146951941511609................forever….
A circle is defined by its diameter or radius The perimeter or circumference of a circle is the distance around the outside radius The Area and Perimeter of a Circle The area of a circle is the space inside it Diameter The ratio of π (pi) The circumference is found using the formula C=π d or C= 2πr (since d=2r) The area is found using the formula A=πr2
A circle is defined by its diameter or radius The perimeter or circumference of a circle is the distance around the outside radius The Area and Perimeter of a Circle The area of a circle is the space inside it Diameter The ratio of π (pi) The circumference is found using the formula C=π d or C= 2πr (since d=2r) The area is found using the formula C=πr2