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Finding the Fourth Proportional to 285.88, 428.72 and 139.52

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Solution

The fourth proportional to 285.88, 428.72 and 139.52 is: 209.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.88 : 428.72 = 139.52 : x
  2. Step 2: Convert to fraction form
    285.88/428.72 = 139.52/x
  3. Step 3: Cross multiply
    285.88x = 428.72 × 139.52
  4. Step 4: Simplify right side
    285.88x = 59,815.01
  5. Step 5: Solve for x
    x = 59,815.01/285.88
  6. Step 6: Final answer
    x = 209.23

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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.