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Finding the Fourth Proportional to 817.46, 1,128 and 485.90

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Solution

The fourth proportional to 817.46, 1,128 and 485.90 is: 670.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.46 : 1,128 = 485.90 : x
  2. Step 2: Convert to fraction form
    817.46/1,128 = 485.90/x
  3. Step 3: Cross multiply
    817.46x = 1,128 × 485.90
  4. Step 4: Simplify right side
    817.46x = 548,095.20
  5. Step 5: Solve for x
    x = 548,095.20/817.46
  6. Step 6: Final answer
    x = 670.49

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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.