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Finding the Fourth Proportional to 215.85, 297.89 and 128.50

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Solution

The fourth proportional to 215.85, 297.89 and 128.50 is: 177.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.85 : 297.89 = 128.50 : x
  2. Step 2: Convert to fraction form
    215.85/297.89 = 128.50/x
  3. Step 3: Cross multiply
    215.85x = 297.89 × 128.50
  4. Step 4: Simplify right side
    215.85x = 38,278.22
  5. Step 5: Solve for x
    x = 38,278.22/215.85
  6. Step 6: Final answer
    x = 177.34

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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.