An isosceles trapezoid has base angles 45 and bases of lengths 9 and 15 the area pf the trapezoid is

Tangent 45 = height / 3
height = 3 * tan (45)
height = 3 * 1
height = 3

Trapezoid area = ((sum of the bases) ÷ 2) • height

Trapezoid area =  (9 + 15) /2 * height

Trapezoid area =  12 * 3

Trapezoid area =  36