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Finding the Fourth Proportional to 136.31, 188.18 and 87.20

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Solution

The fourth proportional to 136.31, 188.18 and 87.20 is: 120.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.31 : 188.18 = 87.20 : x
  2. Step 2: Convert to fraction form
    136.31/188.18 = 87.20/x
  3. Step 3: Cross multiply
    136.31x = 188.18 × 87.20
  4. Step 4: Simplify right side
    136.31x = 16,407.92
  5. Step 5: Solve for x
    x = 16,407.92/136.31
  6. Step 6: Final answer
    x = 120.38

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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.