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Finding the Fourth Proportional to 817.87, 1,128.80 and 486.31

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Solution

The fourth proportional to 817.87, 1,128.80 and 486.31 is: 671.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.87 : 1,128.80 = 486.31 : x
  2. Step 2: Convert to fraction form
    817.87/1,128.80 = 486.31/x
  3. Step 3: Cross multiply
    817.87x = 1,128.80 × 486.31
  4. Step 4: Simplify right side
    817.87x = 548,946.73
  5. Step 5: Solve for x
    x = 548,946.73/817.87
  6. Step 6: Final answer
    x = 671.19

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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.