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Finding the Fourth Proportional to 88.20, 121.70 and 57.12

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Solution

The fourth proportional to 88.20, 121.70 and 57.12 is: 78.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.20 : 121.70 = 57.12 : x
  2. Step 2: Convert to fraction form
    88.20/121.70 = 57.12/x
  3. Step 3: Cross multiply
    88.20x = 121.70 × 57.12
  4. Step 4: Simplify right side
    88.20x = 6,951.33
  5. Step 5: Solve for x
    x = 6,951.33/88.20
  6. Step 6: Final answer
    x = 78.81

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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.