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Finding the Fourth Proportional to 76.87, 106.15 and 65.89

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Solution

The fourth proportional to 76.87, 106.15 and 65.89 is: 90.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.87 : 106.15 = 65.89 : x
  2. Step 2: Convert to fraction form
    76.87/106.15 = 65.89/x
  3. Step 3: Cross multiply
    76.87x = 106.15 × 65.89
  4. Step 4: Simplify right side
    76.87x = 6,993.69
  5. Step 5: Solve for x
    x = 6,993.69/76.87
  6. Step 6: Final answer
    x = 90.99

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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.