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Finding the Fourth Proportional to 88.80, 121.80 and 85.20

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Solution

The fourth proportional to 88.80, 121.80 and 85.20 is: 116.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.80 : 121.80 = 85.20 : x
  2. Step 2: Convert to fraction form
    88.80/121.80 = 85.20/x
  3. Step 3: Cross multiply
    88.80x = 121.80 × 85.20
  4. Step 4: Simplify right side
    88.80x = 10,377.36
  5. Step 5: Solve for x
    x = 10,377.36/88.80
  6. Step 6: Final answer
    x = 116.86

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.