Hi people!!!
(Guess only 3 people will see this by today)
Yeaup, i am hellishly slacking, there seem to be nothing to study for maths.
Ohyea, go to IVLE to dl the Revision 4. [I completed it liao ;D 45min]
For tomorrow maths exam...
Don't make careless mistakes.
Memorize all the formulae [ int ang,ext ang]
I will post most of the formulae below.
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Triangles and Polygons
Sum of interior angles: 180(n-2)
Sum of exterior angles: 360
Perimeters and Areas of Plane Figures
Polygon Formulas
(N = # of sides and S = length from center to a corner)
Area of a regular polygon = (1/2) N sin (360°/N) S2
Sum of the interior angles of a polygon = (N - 2) x 180°
The number of diagonals in a polygon = 1/2 N (N-3)
The number of triangles (when you draw all the diagonals from one vertex) in a polygon = (N - 2)
Area
Rectangle: BH
Triangle: 1/2base*height
Circle: 2
Parallelogram: BH
Square: l2
Length of Arc and Area of Sector
If the radius of the circle is r,
Area of sector = πr2 × A/360
Arc length = 2πr × A/360
In other words, area of sector = area of circle × A/360
arc length = circumference of circle × A/360
