Question 437609
Find  the height of the isosceles trapezoid.

Both base angles are 45 degrees.  Two isosceles right triangles are 
formed from both sides of the trapezoid, and each right triangle has leg {{{(8-4)/2 = 2}}} units long.  Hence the height of the trapezoid is 2.

Its area is {{{A = (h/2)(a+b) = (2/2)(4 + 8) = 12}}} square units.