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Finding the Fourth Proportional to 817.40, 1,128.01 and 485.99

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Solution

The fourth proportional to 817.40, 1,128.01 and 485.99 is: 670.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.40 : 1,128.01 = 485.99 : x
  2. Step 2: Convert to fraction form
    817.40/1,128.01 = 485.99/x
  3. Step 3: Cross multiply
    817.40x = 1,128.01 × 485.99
  4. Step 4: Simplify right side
    817.40x = 548,195.94
  5. Step 5: Solve for x
    x = 548,195.94/817.40
  6. Step 6: Final answer
    x = 670.66

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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.