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Finding the Fourth Proportional to 208.90, 313.15 and 71.91

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Solution

The fourth proportional to 208.90, 313.15 and 71.91 is: 107.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.90 : 313.15 = 71.91 : x
  2. Step 2: Convert to fraction form
    208.90/313.15 = 71.91/x
  3. Step 3: Cross multiply
    208.90x = 313.15 × 71.91
  4. Step 4: Simplify right side
    208.90x = 22,518.44
  5. Step 5: Solve for x
    x = 22,518.44/208.90
  6. Step 6: Final answer
    x = 107.80

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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.