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Finding the Fourth Proportional to 136.90, 188.87 and 87.77

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Solution

The fourth proportional to 136.90, 188.87 and 87.77 is: 121.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.90 : 188.87 = 87.77 : x
  2. Step 2: Convert to fraction form
    136.90/188.87 = 87.77/x
  3. Step 3: Cross multiply
    136.90x = 188.87 × 87.77
  4. Step 4: Simplify right side
    136.90x = 16,577.81
  5. Step 5: Solve for x
    x = 16,577.81/136.90
  6. Step 6: Final answer
    x = 121.10

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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.