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Finding the Fourth Proportional to 101.48, 139.80 and 85.20

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Solution

The fourth proportional to 101.48, 139.80 and 85.20 is: 117.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.48 : 139.80 = 85.20 : x
  2. Step 2: Convert to fraction form
    101.48/139.80 = 85.20/x
  3. Step 3: Cross multiply
    101.48x = 139.80 × 85.20
  4. Step 4: Simplify right side
    101.48x = 11,910.96
  5. Step 5: Solve for x
    x = 11,910.96/101.48
  6. Step 6: Final answer
    x = 117.37

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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.