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Finding the Fourth Proportional to 285.91, 428.86 and 90.90

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Solution

The fourth proportional to 285.91, 428.86 and 90.90 is: 136.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.91 : 428.86 = 90.90 : x
  2. Step 2: Convert to fraction form
    285.91/428.86 = 90.90/x
  3. Step 3: Cross multiply
    285.91x = 428.86 × 90.90
  4. Step 4: Simplify right side
    285.91x = 38,983.37
  5. Step 5: Solve for x
    x = 38,983.37/285.91
  6. Step 6: Final answer
    x = 136.35

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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.