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Finding the Fourth Proportional to 146.15, 219.31 and 85.40

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Solution

The fourth proportional to 146.15, 219.31 and 85.40 is: 128.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    146.15 : 219.31 = 85.40 : x
  2. Step 2: Convert to fraction form
    146.15/219.31 = 85.40/x
  3. Step 3: Cross multiply
    146.15x = 219.31 × 85.40
  4. Step 4: Simplify right side
    146.15x = 18,727.76
  5. Step 5: Solve for x
    x = 18,727.76/146.15
  6. Step 6: Final answer
    x = 128.15

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.