Answer: 259.2
Explanation:
Hi, since the shoe box is a rectangular prism we have to apply the next formula to calculate the surface area if the box: 
Surface area (A) = 2wl + 2lh + 2hw 
Where: 
w = width 
l = length 
h = height 
Replacing with the vales given: 
A = 2 (6x 10)+ 2 ( 10x3)+ 2 (3x 6) 
A = 2 (60) + 2 (30) + 2(18) 
A = 120+ 60+36 
A =216 inches 
Since she needs 20% more than the total surface area in gift wrap, we have to multiply the total surface area by the 20_% in decimal form, and then add that value to the total surface area. 
216 x (20/100) = 43.2 
Adding that value to the total surface area: 
216 + 43.2 = 259.2 square inches