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Finding the Fourth Proportional to 784.78, 1,178.33 and 438.79

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Solution

The fourth proportional to 784.78, 1,178.33 and 438.79 is: 658.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.78 : 1,178.33 = 438.79 : x
  2. Step 2: Convert to fraction form
    784.78/1,178.33 = 438.79/x
  3. Step 3: Cross multiply
    784.78x = 1,178.33 × 438.79
  4. Step 4: Simplify right side
    784.78x = 517,039.42
  5. Step 5: Solve for x
    x = 517,039.42/784.78
  6. Step 6: Final answer
    x = 658.83

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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.