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Finding the Fourth Proportional to 782.31, 1,172.02 and 678.43

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Solution

The fourth proportional to 782.31, 1,172.02 and 678.43 is: 1,016.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.31 : 1,172.02 = 678.43 : x
  2. Step 2: Convert to fraction form
    782.31/1,172.02 = 678.43/x
  3. Step 3: Cross multiply
    782.31x = 1,172.02 × 678.43
  4. Step 4: Simplify right side
    782.31x = 795,127.98
  5. Step 5: Solve for x
    x = 795,127.98/782.31
  6. Step 6: Final answer
    x = 1,016.39

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.