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Finding the Fourth Proportional to 782.85, 1,078.48 and 642.52

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Solution

The fourth proportional to 782.85, 1,078.48 and 642.52 is: 885.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.85 : 1,078.48 = 642.52 : x
  2. Step 2: Convert to fraction form
    782.85/1,078.48 = 642.52/x
  3. Step 3: Cross multiply
    782.85x = 1,078.48 × 642.52
  4. Step 4: Simplify right side
    782.85x = 692,944.97
  5. Step 5: Solve for x
    x = 692,944.97/782.85
  6. Step 6: Final answer
    x = 885.16

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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.