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Finding the Fourth Proportional to 915.78, 1,372.86 and 338.28

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Solution

The fourth proportional to 915.78, 1,372.86 and 338.28 is: 507.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.78 : 1,372.86 = 338.28 : x
  2. Step 2: Convert to fraction form
    915.78/1,372.86 = 338.28/x
  3. Step 3: Cross multiply
    915.78x = 1,372.86 × 338.28
  4. Step 4: Simplify right side
    915.78x = 464,411.08
  5. Step 5: Solve for x
    x = 464,411.08/915.78
  6. Step 6: Final answer
    x = 507.12

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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.