A quadrilateral in which (i) both pairs of opposite sides are parallel and (ii) the lengths of opposite sides are equal. Either property, (i) or (ii), in fact implies the other. The area of a parallelogram equals ‘base times height’. That is to say, if one pair of parallel sides, of length b, are a distance h apart, the area equals bh. Alternatively, if the other pair of sides have length a and θ is the angle between adjacent sides, the area equals absinθ, so the area also equals |a×b|, the magnitude of the vector product of the sides as vectors.
A parallelogram
- cataclasis
- cataclasite
- cataclysmic binary
- cataclysmic variable
- catacomb
- catadioptric system
- catagenesis
- Catalan numbers
- Catalan’s conjecture
- Catalan’s constant
- catalase
- Catalaunian Fields
- Catalina Sky Survey
- catalogue equinox
- catalysis
- catalyst
- catalyst poison
- catalytic activity
- catalytic coefficient
- catalytic converter
- catalytic cracking
- catalytic distillation
- catalytic hydrocracking
- catalytic reactor
- catalytic reforming