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Finding the Fourth Proportional to 669.12, 1,003.68 and 380.80

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Solution

The fourth proportional to 669.12, 1,003.68 and 380.80 is: 571.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.12 : 1,003.68 = 380.80 : x
  2. Step 2: Convert to fraction form
    669.12/1,003.68 = 380.80/x
  3. Step 3: Cross multiply
    669.12x = 1,003.68 × 380.80
  4. Step 4: Simplify right side
    669.12x = 382,201.34
  5. Step 5: Solve for x
    x = 382,201.34/669.12
  6. Step 6: Final answer
    x = 571.20

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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.