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Finding the Fourth Proportional to 782.60, 1,080.20 and 487.70

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Solution

The fourth proportional to 782.60, 1,080.20 and 487.70 is: 673.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.60 : 1,080.20 = 487.70 : x
  2. Step 2: Convert to fraction form
    782.60/1,080.20 = 487.70/x
  3. Step 3: Cross multiply
    782.60x = 1,080.20 × 487.70
  4. Step 4: Simplify right side
    782.60x = 526,809.36
  5. Step 5: Solve for x
    x = 526,809.36/782.60
  6. Step 6: Final answer
    x = 673.15

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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.