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Finding the Fourth Proportional to 76.70, 105.72 and 57.74

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Solution

The fourth proportional to 76.70, 105.72 and 57.74 is: 79.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.70 : 105.72 = 57.74 : x
  2. Step 2: Convert to fraction form
    76.70/105.72 = 57.74/x
  3. Step 3: Cross multiply
    76.70x = 105.72 × 57.74
  4. Step 4: Simplify right side
    76.70x = 6,104.27
  5. Step 5: Solve for x
    x = 6,104.27/76.70
  6. Step 6: Final answer
    x = 79.59

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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.