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Finding the Fourth Proportional to 76.50, 105.57 and 42

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Solution

The fourth proportional to 76.50, 105.57 and 42 is: 57.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.50 : 105.57 = 42 : x
  2. Step 2: Convert to fraction form
    76.50/105.57 = 42/x
  3. Step 3: Cross multiply
    76.50x = 105.57 × 42
  4. Step 4: Simplify right side
    76.50x = 4,433.94
  5. Step 5: Solve for x
    x = 4,433.94/76.50
  6. Step 6: Final answer
    x = 57.96

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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.