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Finding the Fourth Proportional to 101.21, 139.65 and 66.20

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Solution

The fourth proportional to 101.21, 139.65 and 66.20 is: 91.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.21 : 139.65 = 66.20 : x
  2. Step 2: Convert to fraction form
    101.21/139.65 = 66.20/x
  3. Step 3: Cross multiply
    101.21x = 139.65 × 66.20
  4. Step 4: Simplify right side
    101.21x = 9,244.83
  5. Step 5: Solve for x
    x = 9,244.83/101.21
  6. Step 6: Final answer
    x = 91.34

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.