All basic formulas for trapezoid
Side of a trapezoid
1. To find the missing base length of a trapezoid (called a trapezium in the UK) if you know other base and midsegment
1. To find the missing base length of a trapezoid (called a trapezium in the UK) if you know other base and midsegment
, 
- bases of a trapezoid
- middle line
2. To find the legs and bases of a trapezoid (trapezium UK) with height, angle and other sides
, - bases
, 
- legs of a trapezoid
, 
- angles at the base
- height
3. To find bases of a trapezoid (trapezium UK) with height, diagonals and angle between them
, - bases
, 
- diagonals
, 
- angles between the diagonals
- height
* It is true in this case:
Diagonal of a trapezoid
1. Diagonals of a trapezoid if you know sides and angles at the base
, 
- bases
, 
- legs
, 
- angles at the base
, 
- diagonals
) :
) :
2. Diagonals of a trapezoid using height
, - bases
, - legs
, - angles at the base
, - diagonals
- height
) :
3. Diagonals of a trapezoid if you know other diagonal, angle between the diagonals and height or area or midsegment
, - bases
, - diagonals
, - angles between the diagonals
- height
- midsegment
- areaof a trapezoid
) :
* It is true in this case:
4. Diagonals of a trapezoid using formula for the sum of the squared diagonals
- lower base
- upper base
, - legs
, - diagonals
) :
Midline of a trapezoid
1. Median of a trapezoid (also known as midline or midsegment) if you know bases
, - bases
- midline
) :
2. Median of a trapezoid (also known as midline or midsegment), if you know base, height and angles at the base
- lower base
- upper base
, - angles at the base
- height
- midline
) :
3. Median of a trapezoid (also known as midline or midsegment), if you know diagonals, height and angle between the diagonals
, - diagonals
, - angles between the diagonals
- height
- midline
) :
* It is true in this case:
4. Median of a trapezoid (also known as midline or midsegment), if you know height and area of a trapezoid
- areaof a trapezoid
- height
- midline
) :
Height of a trapezoid
1. Height of a trapezoid if you know only sides or sides and angle at the base
, - bases
, - legs (lateral side)
, - angles at the base
- height
) :
) :
2. Height of a trapezoid if you know diagonals, angle between the diagonals and bases or midline
, - bases
, - diagonals
, - angles between the diagonals
- midline
- height
) :
) :
3. Height of a trapezoid if you know area of a trapezoid
, - bases
- area
- midline
- height
) :
