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Finding the Fourth Proportional to 136.77, 188.78 and 87.65

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Solution

The fourth proportional to 136.77, 188.78 and 87.65 is: 120.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.77 : 188.78 = 87.65 : x
  2. Step 2: Convert to fraction form
    136.77/188.78 = 87.65/x
  3. Step 3: Cross multiply
    136.77x = 188.78 × 87.65
  4. Step 4: Simplify right side
    136.77x = 16,546.57
  5. Step 5: Solve for x
    x = 16,546.57/136.77
  6. Step 6: Final answer
    x = 120.98

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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.