I'll do the first part to get you started.
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Area = 1/2
Length = 7/8
Width = W
Area of rectangle = Length*Width
A = L*W
1/2 = (7/8)*W
(8/7)*(1/2) = (8/7)*(7/8)*W .... see note1 below
(8*1)/(7*2) = (8*7)/(7*8)*W .... see note2
8/14 = (56/56)*W
4/7 = 1*W .... see note3 and note4
W = 4/7
Final Answer: 4/7
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Foot notes
- note1: I multiplied both sides by the reciprocal of 7/8, that way the "7/8" on the right side cancels out (as you'll see in a few steps later)
- note2: I used the rule (a/b)*(c/d) = (a*c)/(b*d)
- note3: the 56/56 turns into 1, and later on 1*W becomes just W
- note4: 8/14 reduces to 4/7 after dividing both parts by 2
