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Finding the Fourth Proportional to 817.48, 1,128.21 and 485.98

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Solution

The fourth proportional to 817.48, 1,128.21 and 485.98 is: 670.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.48 : 1,128.21 = 485.98 : x
  2. Step 2: Convert to fraction form
    817.48/1,128.21 = 485.98/x
  3. Step 3: Cross multiply
    817.48x = 1,128.21 × 485.98
  4. Step 4: Simplify right side
    817.48x = 548,287.50
  5. Step 5: Solve for x
    x = 548,287.50/817.48
  6. Step 6: Final answer
    x = 670.70

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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.