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Finding the Fourth Proportional to 669.87, 1,005.21 and 259.20

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Solution

The fourth proportional to 669.87, 1,005.21 and 259.20 is: 388.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.87 : 1,005.21 = 259.20 : x
  2. Step 2: Convert to fraction form
    669.87/1,005.21 = 259.20/x
  3. Step 3: Cross multiply
    669.87x = 1,005.21 × 259.20
  4. Step 4: Simplify right side
    669.87x = 260,550.43
  5. Step 5: Solve for x
    x = 260,550.43/669.87
  6. Step 6: Final answer
    x = 388.96

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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.