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Finding the Fourth Proportional to 77.70, 116.38 and 47.20

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Solution

The fourth proportional to 77.70, 116.38 and 47.20 is: 70.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.70 : 116.38 = 47.20 : x
  2. Step 2: Convert to fraction form
    77.70/116.38 = 47.20/x
  3. Step 3: Cross multiply
    77.70x = 116.38 × 47.20
  4. Step 4: Simplify right side
    77.70x = 5,493.14
  5. Step 5: Solve for x
    x = 5,493.14/77.70
  6. Step 6: Final answer
    x = 70.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.