S = MN * h
S = 42 * h
h = a * sin a = 40 * sin45° = 40 * √2 / 2 = 20√2 / 2 = 10√2
S = 42 * 10√2 = 210
S = MN * h
S = 42 * h
h = a * sin a = 40 * sin45° = 40 * √2 / 2 = 20√2 / 2 = 10√2
S = 42 * 10√2 = 210