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Finding the Fourth Proportional to 76.87, 105.82 and 57.16

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Solution

The fourth proportional to 76.87, 105.82 and 57.16 is: 78.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.87 : 105.82 = 57.16 : x
  2. Step 2: Convert to fraction form
    76.87/105.82 = 57.16/x
  3. Step 3: Cross multiply
    76.87x = 105.82 × 57.16
  4. Step 4: Simplify right side
    76.87x = 6,048.67
  5. Step 5: Solve for x
    x = 6,048.67/76.87
  6. Step 6: Final answer
    x = 78.69

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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.