Find length of the 4 identical triangles:
Lets take 1 of them
Height= 3.75/2
Triangle area= 1/2bh
Triangle area= 0.5*0.75*1.875
Triangle area= 0.703 in
Area*4= 2.81 inches squared
Find area of rectangle
Rectangle area= LW
Area= 3.25*3.75
Area=12.2 inches squared
Total area= 2.81+12.2
Total area=14.9 inches squared
Hope this helps :)