Angle Classification
Perimeter- Area Formulas
- Volume Formulas
- Triangles
- Parallelogram
- Circle
- Central Median
- Pythagorean Theorem Problems
- Sine Cosine Rule
- Trigonometry
- Definition of line slope
- Vectors
- Analytic Geometry
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Area Formulas
The standard notation for area is S
Square
Let's a square side is long a then area formula is:
S = a.a = a2
Rectangle
Let's a rectangle sides are long a and b
S = a.b
Parallelogram
Let's palallelogram sides are long a and b and
ha is the altitude to the side a,
and hb is the altitude to the side b
Parallelogram area formula is:
S = a.ha = b.hb
Trapezoid
Say the length of the parallel sides of a trapezoid are long a and b and the distance between the two bases is h(the trapezoid altitude). The area formula is:
S = ½(a + b)h
Triangle
ABC is triangle
S = ½(a.ha) = ½(b.hb) = ½(c.hc)
S = ½(ab.sinC) = ½(ac.sinB) = ½(bc.sinA)
p = ½(a + b + c)
S = ½(ab.sinC) = ½(ac.sinB) = ½(bc.sinA)
S = √p(p - a)(p - b)(p - c) - Heron formula
S = R2sinA.sinB.sinC = abc/4R
if you want to see the formula for circles area go to circles
