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Finding the Fourth Proportional to 718.78, 991.92 and 439.03

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Solution

The fourth proportional to 718.78, 991.92 and 439.03 is: 605.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.78 : 991.92 = 439.03 : x
  2. Step 2: Convert to fraction form
    718.78/991.92 = 439.03/x
  3. Step 3: Cross multiply
    718.78x = 991.92 × 439.03
  4. Step 4: Simplify right side
    718.78x = 435,482.64
  5. Step 5: Solve for x
    x = 435,482.64/718.78
  6. Step 6: Final answer
    x = 605.86

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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.