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Finding the Fourth Proportional to 492.12, 678.78 and 423

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Solution

The fourth proportional to 492.12, 678.78 and 423 is: 583.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    492.12 : 678.78 = 423 : x
  2. Step 2: Convert to fraction form
    492.12/678.78 = 423/x
  3. Step 3: Cross multiply
    492.12x = 678.78 × 423
  4. Step 4: Simplify right side
    492.12x = 287,123.94
  5. Step 5: Solve for x
    x = 287,123.94/492.12
  6. Step 6: Final answer
    x = 583.44

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.