Where did the 4.8r,4x, 1.4,4.26,1.44,2.84 come from? basically I cant understand how to do these types of questions :(

If anyone could explain in depth and how to do step by step I would really appreciate it! thank you so much!

2. [12 points] You have 7.1 cm of wire that you will use to create two shapes: a sector with central angle 2.8 radians, and a square. What is the minimum possible combined area of the two shapes: 2 8 X A = 3(2.8 ) r2 +x2 X 2.8 r 4. 8 r + 4 x = 7.1 4 x = 7.1 - 4.8 r 4 x= t.1 - 1. 2r A = 1.4,2 + ( 4 = 1.4-2+ 242 - 4.265 + 1.44,3 ) = 2.84+7 - 4.26 r + 3. 150625 A A (-4.26 ) N k = 3. 150625 - ~ | 553 sq. Cm 4 (2. 84 ) K 75