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Finding the Fourth Proportional to 915.05, 1,372.58 and 428.65

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Solution

The fourth proportional to 915.05, 1,372.58 and 428.65 is: 642.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.05 : 1,372.58 = 428.65 : x
  2. Step 2: Convert to fraction form
    915.05/1,372.58 = 428.65/x
  3. Step 3: Cross multiply
    915.05x = 1,372.58 × 428.65
  4. Step 4: Simplify right side
    915.05x = 588,347.41
  5. Step 5: Solve for x
    x = 588,347.41/915.05
  6. Step 6: Final answer
    x = 642.97

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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.