You will need
• To know the area of a trapezoid, the lengths of the bases and also the length of the middle line.
Instruction
1
In order to calculate the area of a trapezoid, you must use the following formula:

S = ((a+b)*h)/2, where a and b are the bases of the trapezoid, h is the height of the trapezoid.

In that case, if the area and lengths of bases are known, find the elevation by the formula:

h = (2*S)/(a+b)
2
If the trapeze is known for its size and length of the middle line, then find its height will not be difficult:

S = m*h where m is the middle line here:

h = S/m.
3
In order to make both more understandable, you can give a couple of examples.

Example 1: length of the midline of the trapezoid is 10 cm, its area is 100 cm2. To find the height of the trapezoid is necessary to perform the action:

h = 100/10 = 10 cm

Answer: the height of this trapezoid is 10 cm

Example 2: the area of the trapezoid is 100 cm2, the length of the bases equal to 8 cm and 12 cm find the height of the trapezoid need to run the action:

h = (2*100)/(8+12) = 200/20 = 10 cm

Answer: the height of this trapezoid is 20 cm