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Finding the Fourth Proportional to 782.11, 1,079.29 and 428.05

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Solution

The fourth proportional to 782.11, 1,079.29 and 428.05 is: 590.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.11 : 1,079.29 = 428.05 : x
  2. Step 2: Convert to fraction form
    782.11/1,079.29 = 428.05/x
  3. Step 3: Cross multiply
    782.11x = 1,079.29 × 428.05
  4. Step 4: Simplify right side
    782.11x = 461,987.10
  5. Step 5: Solve for x
    x = 461,987.10/782.11
  6. Step 6: Final answer
    x = 590.70

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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.