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Finding the Fourth Proportional to 208.18, 312.39 and 78.27

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Solution

The fourth proportional to 208.18, 312.39 and 78.27 is: 117.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.18 : 312.39 = 78.27 : x
  2. Step 2: Convert to fraction form
    208.18/312.39 = 78.27/x
  3. Step 3: Cross multiply
    208.18x = 312.39 × 78.27
  4. Step 4: Simplify right side
    208.18x = 24,450.77
  5. Step 5: Solve for x
    x = 24,450.77/208.18
  6. Step 6: Final answer
    x = 117.45

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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.