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Finding the Fourth Proportional to 782.80, 1,080.28 and 428.74

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Solution

The fourth proportional to 782.80, 1,080.28 and 428.74 is: 591.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.80 : 1,080.28 = 428.74 : x
  2. Step 2: Convert to fraction form
    782.80/1,080.28 = 428.74/x
  3. Step 3: Cross multiply
    782.80x = 1,080.28 × 428.74
  4. Step 4: Simplify right side
    782.80x = 463,161.95
  5. Step 5: Solve for x
    x = 463,161.95/782.80
  6. Step 6: Final answer
    x = 591.68

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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.