first one
use pythagorean theorem to find the height as in diagram atachmetn
4^2+h^2=8^2
16+h^2=64
minus 16
h^2=48
sqrt both sides
h=4√3
area=1/2bh
area=1/2(4)4√3
area=8√3
aprox
area=13.8
round
area=14cm^2
but that is only 1 triangle so double it
14*2=28cm^2
same as other, just cut along the black center line and rearanged
28 in^2