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Finding the Fourth Proportional to 915.30, 1,373.21 and 421.86

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Solution

The fourth proportional to 915.30, 1,373.21 and 421.86 is: 632.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.30 : 1,373.21 = 421.86 : x
  2. Step 2: Convert to fraction form
    915.30/1,373.21 = 421.86/x
  3. Step 3: Cross multiply
    915.30x = 1,373.21 × 421.86
  4. Step 4: Simplify right side
    915.30x = 579,306.99
  5. Step 5: Solve for x
    x = 579,306.99/915.30
  6. Step 6: Final answer
    x = 632.91

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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.