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Finding the Fourth Proportional to 669.28, 923.84 and 421

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Solution

The fourth proportional to 669.28, 923.84 and 421 is: 581.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.28 : 923.84 = 421 : x
  2. Step 2: Convert to fraction form
    669.28/923.84 = 421/x
  3. Step 3: Cross multiply
    669.28x = 923.84 × 421
  4. Step 4: Simplify right side
    669.28x = 388,936.64
  5. Step 5: Solve for x
    x = 388,936.64/669.28
  6. Step 6: Final answer
    x = 581.13

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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.