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Finding the Fourth Proportional to 101.28, 139.68 and 90.48

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Solution

The fourth proportional to 101.28, 139.68 and 90.48 is: 124.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.28 : 139.68 = 90.48 : x
  2. Step 2: Convert to fraction form
    101.28/139.68 = 90.48/x
  3. Step 3: Cross multiply
    101.28x = 139.68 × 90.48
  4. Step 4: Simplify right side
    101.28x = 12,638.25
  5. Step 5: Solve for x
    x = 12,638.25/101.28
  6. Step 6: Final answer
    x = 124.79

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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.