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Finding the Fourth Proportional to 782.45, 1,079.89 and 487.81

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Solution

The fourth proportional to 782.45, 1,079.89 and 487.81 is: 673.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.45 : 1,079.89 = 487.81 : x
  2. Step 2: Convert to fraction form
    782.45/1,079.89 = 487.81/x
  3. Step 3: Cross multiply
    782.45x = 1,079.89 × 487.81
  4. Step 4: Simplify right side
    782.45x = 526,775.74
  5. Step 5: Solve for x
    x = 526,775.74/782.45
  6. Step 6: Final answer
    x = 673.24

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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.