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Finding the Fourth Proportional to 77.50, 106.88 and 49.89

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Solution

The fourth proportional to 77.50, 106.88 and 49.89 is: 68.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.50 : 106.88 = 49.89 : x
  2. Step 2: Convert to fraction form
    77.50/106.88 = 49.89/x
  3. Step 3: Cross multiply
    77.50x = 106.88 × 49.89
  4. Step 4: Simplify right side
    77.50x = 5,331.99
  5. Step 5: Solve for x
    x = 5,331.99/77.50
  6. Step 6: Final answer
    x = 68.80

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.