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Finding the Fourth Proportional to 492.78, 679.80 and 318.09

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Solution

The fourth proportional to 492.78, 679.80 and 318.09 is: 438.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    492.78 : 679.80 = 318.09 : x
  2. Step 2: Convert to fraction form
    492.78/679.80 = 318.09/x
  3. Step 3: Cross multiply
    492.78x = 679.80 × 318.09
  4. Step 4: Simplify right side
    492.78x = 216,237.58
  5. Step 5: Solve for x
    x = 216,237.58/492.78
  6. Step 6: Final answer
    x = 438.81

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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.