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Finding the Fourth Proportional to 669.20, 923.21 and 420.35

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Solution

The fourth proportional to 669.20, 923.21 and 420.35 is: 579.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.20 : 923.21 = 420.35 : x
  2. Step 2: Convert to fraction form
    669.20/923.21 = 420.35/x
  3. Step 3: Cross multiply
    669.20x = 923.21 × 420.35
  4. Step 4: Simplify right side
    669.20x = 388,071.32
  5. Step 5: Solve for x
    x = 388,071.32/669.20
  6. Step 6: Final answer
    x = 579.90

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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.