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Finding the Fourth Proportional to 289.57, 399.31 and 210.90

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Solution

The fourth proportional to 289.57, 399.31 and 210.90 is: 290.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.57 : 399.31 = 210.90 : x
  2. Step 2: Convert to fraction form
    289.57/399.31 = 210.90/x
  3. Step 3: Cross multiply
    289.57x = 399.31 × 210.90
  4. Step 4: Simplify right side
    289.57x = 84,214.48
  5. Step 5: Solve for x
    x = 84,214.48/289.57
  6. Step 6: Final answer
    x = 290.83

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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.