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Finding the Fourth Proportional to 217.80, 297.90 and 212.40

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Solution

The fourth proportional to 217.80, 297.90 and 212.40 is: 290.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    217.80 : 297.90 = 212.40 : x
  2. Step 2: Convert to fraction form
    217.80/297.90 = 212.40/x
  3. Step 3: Cross multiply
    217.80x = 297.90 × 212.40
  4. Step 4: Simplify right side
    217.80x = 63,273.96
  5. Step 5: Solve for x
    x = 63,273.96/217.80
  6. Step 6: Final answer
    x = 290.51

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.