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Finding the Fourth Proportional to 77.70, 107.20 and 53.15

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Solution

The fourth proportional to 77.70, 107.20 and 53.15 is: 73.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.70 : 107.20 = 53.15 : x
  2. Step 2: Convert to fraction form
    77.70/107.20 = 53.15/x
  3. Step 3: Cross multiply
    77.70x = 107.20 × 53.15
  4. Step 4: Simplify right side
    77.70x = 5,697.68
  5. Step 5: Solve for x
    x = 5,697.68/77.70
  6. Step 6: Final answer
    x = 73.33

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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.