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Finding the Fourth Proportional to 787.24, 1,179.78 and 421.30

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Solution

The fourth proportional to 787.24, 1,179.78 and 421.30 is: 631.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.24 : 1,179.78 = 421.30 : x
  2. Step 2: Convert to fraction form
    787.24/1,179.78 = 421.30/x
  3. Step 3: Cross multiply
    787.24x = 1,179.78 × 421.30
  4. Step 4: Simplify right side
    787.24x = 497,043.58
  5. Step 5: Solve for x
    x = 497,043.58/787.24
  6. Step 6: Final answer
    x = 631.38

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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.