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Finding the Fourth Proportional to 817.85, 1,128.47 and 486.15

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Solution

The fourth proportional to 817.85, 1,128.47 and 486.15 is: 670.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.85 : 1,128.47 = 486.15 : x
  2. Step 2: Convert to fraction form
    817.85/1,128.47 = 486.15/x
  3. Step 3: Cross multiply
    817.85x = 1,128.47 × 486.15
  4. Step 4: Simplify right side
    817.85x = 548,603.26
  5. Step 5: Solve for x
    x = 548,603.26/817.85
  6. Step 6: Final answer
    x = 670.79

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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.