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Finding the Fourth Proportional to 212.87, 293.78 and 128.87

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Solution

The fourth proportional to 212.87, 293.78 and 128.87 is: 177.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.87 : 293.78 = 128.87 : x
  2. Step 2: Convert to fraction form
    212.87/293.78 = 128.87/x
  3. Step 3: Cross multiply
    212.87x = 293.78 × 128.87
  4. Step 4: Simplify right side
    212.87x = 37,857.83
  5. Step 5: Solve for x
    x = 37,857.83/212.87
  6. Step 6: Final answer
    x = 177.85

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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.