SCREEN 9
CLS
a = 50
b = 50
c = 20
d = 90
e = 100
f = 90
LINE (a, b)-(c, d)
LINE (c, d)-(e, f)
LINE (e, f)-(a, b)
PAINT ((a + c + e) / 3, (b + d + f) / 3), 15, 15