Full tank: n gallons
Amount bought today: 4.25 gallons
Before she filled the motorcyle we know that:
* It must be a non-negative amount of gas in the tank.
* It was at most n - 4.25 gallons of gas in the tank before she filled it.
(she filled 4.25 gallons into the tank after all)
Therefore the amont of gas g, in gallons can be expressed as follows:
0 ≤ g ≤ n - 4.25 or equaly: g ∈ [0, n - 4.25]
Would be very helpful if you could specify what geometric object you would like to know the area of.
Nontheless here are a few formula for the area of polygons and circles:
square: A = s2, s: length of one side
rectangle: A = lw, (length * width)
circle: A = pi * r2, r: radius
triangle: A = bh/2, b: base, h: height
quadrilateral: A = pq sin t, (p and q are the length of the diagonals, and t is the angle between them)
parallelogram A = bh (base * heigth)
rhombus: A = pq/2 (p and q are the length of the diagonals)
trapezoid: (a + b)h/2 (a and b are the length of the parallel sides, h is the heigth)
ellipse: pi * ab, (a and b are the semi-major and the semi-minor axes)