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Finding the Fourth Proportional to 915.40, 1,372.38 and 427.96

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Solution

The fourth proportional to 915.40, 1,372.38 and 427.96 is: 641.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.40 : 1,372.38 = 427.96 : x
  2. Step 2: Convert to fraction form
    915.40/1,372.38 = 427.96/x
  3. Step 3: Cross multiply
    915.40x = 1,372.38 × 427.96
  4. Step 4: Simplify right side
    915.40x = 587,323.74
  5. Step 5: Solve for x
    x = 587,323.74/915.40
  6. Step 6: Final answer
    x = 641.60

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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.