As shown in Figure 2-4-2, Cang uses a square cardboard with a length of 27.6cm to cut out four squares with a side length of 3.8 to form a mask with eyes, nose and mouth.

It should be d

Area of square cardboard: 27.6*27.6=76 1.76.

Area of four squares: 3.8*3.8*4=57.76.

Mask area: 76 1.76-57.76=704.

It should be like this.