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Finding the Fourth Proportional to 76.65, 105.78 and 45.56

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Solution

The fourth proportional to 76.65, 105.78 and 45.56 is: 62.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.65 : 105.78 = 45.56 : x
  2. Step 2: Convert to fraction form
    76.65/105.78 = 45.56/x
  3. Step 3: Cross multiply
    76.65x = 105.78 × 45.56
  4. Step 4: Simplify right side
    76.65x = 4,819.11
  5. Step 5: Solve for x
    x = 4,819.11/76.65
  6. Step 6: Final answer
    x = 62.88

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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.