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Finding the Fourth Proportional to 915.21, 1,372.80 and 395.55

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Solution

The fourth proportional to 915.21, 1,372.80 and 395.55 is: 593.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.21 : 1,372.80 = 395.55 : x
  2. Step 2: Convert to fraction form
    915.21/1,372.80 = 395.55/x
  3. Step 3: Cross multiply
    915.21x = 1,372.80 × 395.55
  4. Step 4: Simplify right side
    915.21x = 543,011.04
  5. Step 5: Solve for x
    x = 543,011.04/915.21
  6. Step 6: Final answer
    x = 593.32

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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.