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Finding the Fourth Proportional to 787.46, 1,178.76 and 421.34

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Solution

The fourth proportional to 787.46, 1,178.76 and 421.34 is: 630.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.46 : 1,178.76 = 421.34 : x
  2. Step 2: Convert to fraction form
    787.46/1,178.76 = 421.34/x
  3. Step 3: Cross multiply
    787.46x = 1,178.76 × 421.34
  4. Step 4: Simplify right side
    787.46x = 496,658.74
  5. Step 5: Solve for x
    x = 496,658.74/787.46
  6. Step 6: Final answer
    x = 630.71

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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.