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Finding the Fourth Proportional to 285.31, 428.10 and 90.34

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Solution

The fourth proportional to 285.31, 428.10 and 90.34 is: 135.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.31 : 428.10 = 90.34 : x
  2. Step 2: Convert to fraction form
    285.31/428.10 = 90.34/x
  3. Step 3: Cross multiply
    285.31x = 428.10 × 90.34
  4. Step 4: Simplify right side
    285.31x = 38,674.48
  5. Step 5: Solve for x
    x = 38,674.48/285.31
  6. Step 6: Final answer
    x = 135.55

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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.