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Finding the Fourth Proportional to 101.30, 139.61 and 85.79

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Solution

The fourth proportional to 101.30, 139.61 and 85.79 is: 118.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.30 : 139.61 = 85.79 : x
  2. Step 2: Convert to fraction form
    101.30/139.61 = 85.79/x
  3. Step 3: Cross multiply
    101.30x = 139.61 × 85.79
  4. Step 4: Simplify right side
    101.30x = 11,977.71
  5. Step 5: Solve for x
    x = 11,977.71/101.30
  6. Step 6: Final answer
    x = 118.25

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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.