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Finding the Fourth Proportional to 208.79, 313.09 and 71.85

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Solution

The fourth proportional to 208.79, 313.09 and 71.85 is: 107.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.79 : 313.09 = 71.85 : x
  2. Step 2: Convert to fraction form
    208.79/313.09 = 71.85/x
  3. Step 3: Cross multiply
    208.79x = 313.09 × 71.85
  4. Step 4: Simplify right side
    208.79x = 22,494.07
  5. Step 5: Solve for x
    x = 22,494.07/208.79
  6. Step 6: Final answer
    x = 107.74

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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.