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Finding the Fourth Proportional to 71.80, 107.76 and 39.76

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Solution

The fourth proportional to 71.80, 107.76 and 39.76 is: 59.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.80 : 107.76 = 39.76 : x
  2. Step 2: Convert to fraction form
    71.80/107.76 = 39.76/x
  3. Step 3: Cross multiply
    71.80x = 107.76 × 39.76
  4. Step 4: Simplify right side
    71.80x = 4,284.54
  5. Step 5: Solve for x
    x = 4,284.54/71.80
  6. Step 6: Final answer
    x = 59.67

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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.