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Finding the Fourth Proportional to 817.39, 1,128 and 485.83

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Solution

The fourth proportional to 817.39, 1,128 and 485.83 is: 670.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.39 : 1,128 = 485.83 : x
  2. Step 2: Convert to fraction form
    817.39/1,128 = 485.83/x
  3. Step 3: Cross multiply
    817.39x = 1,128 × 485.83
  4. Step 4: Simplify right side
    817.39x = 548,016.24
  5. Step 5: Solve for x
    x = 548,016.24/817.39
  6. Step 6: Final answer
    x = 670.45

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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.