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Finding the Fourth Proportional to 817.66, 1,128.02 and 485.90

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Solution

The fourth proportional to 817.66, 1,128.02 and 485.90 is: 670.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.66 : 1,128.02 = 485.90 : x
  2. Step 2: Convert to fraction form
    817.66/1,128.02 = 485.90/x
  3. Step 3: Cross multiply
    817.66x = 1,128.02 × 485.90
  4. Step 4: Simplify right side
    817.66x = 548,104.51
  5. Step 5: Solve for x
    x = 548,104.51/817.66
  6. Step 6: Final answer
    x = 670.34

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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.