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Finding the Fourth Proportional to 669.15, 923.87 and 420.85

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Solution

The fourth proportional to 669.15, 923.87 and 420.85 is: 581.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.15 : 923.87 = 420.85 : x
  2. Step 2: Convert to fraction form
    669.15/923.87 = 420.85/x
  3. Step 3: Cross multiply
    669.15x = 923.87 × 420.85
  4. Step 4: Simplify right side
    669.15x = 388,810.69
  5. Step 5: Solve for x
    x = 388,810.69/669.15
  6. Step 6: Final answer
    x = 581.05

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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.