Ineed with finding the area of the following triangles

1) 1/2 x (4)(3) = 1/2 x 12=6in2
2) 1/2 x (12)(6) = 1/2 x 36=18cm2
3) 1/2 x (9)(7) = 1/2 x 63=31.5ft2
4) 1/2 x (12)(12) = 1/2 x 144= 72cm2
5) 1/2 x (3)(2) = 1/2 x 6=3ft2
6) 1/2 x (20)(16) = 1/2 x 320=160cm2
7) 1/2 x (7)(15) = 1/2 x 105=52.5m2
8) 1/2 x (9)(9) = 1/2 x 81=40.5in2
9) 1/2 x (2)(2) = 1/2 x 4=2ft2
10) 1/2 x (6)(4) = 1/2 x 24=12ft2
11) 1/2 x (15)(10) = 1/2 x 150=75ft2
12) 1/2 x (3)(10) = 1/2 x 30=15m2