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Finding the Fourth Proportional to 645.87, 969.05 and 213.15

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Solution

The fourth proportional to 645.87, 969.05 and 213.15 is: 319.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.87 : 969.05 = 213.15 : x
  2. Step 2: Convert to fraction form
    645.87/969.05 = 213.15/x
  3. Step 3: Cross multiply
    645.87x = 969.05 × 213.15
  4. Step 4: Simplify right side
    645.87x = 206,551.94
  5. Step 5: Solve for x
    x = 206,551.94/645.87
  6. Step 6: Final answer
    x = 319.80

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.