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Finding the Fourth Proportional to 669.70, 924.12 and 421

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Solution

The fourth proportional to 669.70, 924.12 and 421 is: 580.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.70 : 924.12 = 421 : x
  2. Step 2: Convert to fraction form
    669.70/924.12 = 421/x
  3. Step 3: Cross multiply
    669.70x = 924.12 × 421
  4. Step 4: Simplify right side
    669.70x = 389,054.52
  5. Step 5: Solve for x
    x = 389,054.52/669.70
  6. Step 6: Final answer
    x = 580.94

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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.