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Finding the Fourth Proportional to 782.70, 1,080.72 and 708.72

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Solution

The fourth proportional to 782.70, 1,080.72 and 708.72 is: 978.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.70 : 1,080.72 = 708.72 : x
  2. Step 2: Convert to fraction form
    782.70/1,080.72 = 708.72/x
  3. Step 3: Cross multiply
    782.70x = 1,080.72 × 708.72
  4. Step 4: Simplify right side
    782.70x = 765,927.88
  5. Step 5: Solve for x
    x = 765,927.88/782.70
  6. Step 6: Final answer
    x = 978.57

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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.