teman2 tolong bantu ya.. beserta caranya

a² = c² - b²
a² = 5² - 4²
a² = 25 - 16
a = √9
   = 3cm

V = Lt
    = (x + y)a/2 * t
    = (12 + 20)3/2 * 25
    = 32 * 3/2 * 25
    = 16 * 75
    = 1.200 cm³