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Finding the Fourth Proportional to 718.20, 991.31 and 423.57

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Solution

The fourth proportional to 718.20, 991.31 and 423.57 is: 584.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.20 : 991.31 = 423.57 : x
  2. Step 2: Convert to fraction form
    718.20/991.31 = 423.57/x
  3. Step 3: Cross multiply
    718.20x = 991.31 × 423.57
  4. Step 4: Simplify right side
    718.20x = 419,883.34
  5. Step 5: Solve for x
    x = 419,883.34/718.20
  6. Step 6: Final answer
    x = 584.63

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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.