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Finding the Fourth Proportional to 321.86, 482.79 and 78.39

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Solution

The fourth proportional to 321.86, 482.79 and 78.39 is: 117.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.86 : 482.79 = 78.39 : x
  2. Step 2: Convert to fraction form
    321.86/482.79 = 78.39/x
  3. Step 3: Cross multiply
    321.86x = 482.79 × 78.39
  4. Step 4: Simplify right side
    321.86x = 37,845.91
  5. Step 5: Solve for x
    x = 37,845.91/321.86
  6. Step 6: Final answer
    x = 117.59

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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.