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Finding the Fourth Proportional to 208.85, 313.32 and 78.86

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Solution

The fourth proportional to 208.85, 313.32 and 78.86 is: 118.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.85 : 313.32 = 78.86 : x
  2. Step 2: Convert to fraction form
    208.85/313.32 = 78.86/x
  3. Step 3: Cross multiply
    208.85x = 313.32 × 78.86
  4. Step 4: Simplify right side
    208.85x = 24,708.42
  5. Step 5: Solve for x
    x = 24,708.42/208.85
  6. Step 6: Final answer
    x = 118.31

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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.