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Finding the Fourth Proportional to 817.21, 1,127.82 and 485.70

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Solution

The fourth proportional to 817.21, 1,127.82 and 485.70 is: 670.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.21 : 1,127.82 = 485.70 : x
  2. Step 2: Convert to fraction form
    817.21/1,127.82 = 485.70/x
  3. Step 3: Cross multiply
    817.21x = 1,127.82 × 485.70
  4. Step 4: Simplify right side
    817.21x = 547,782.17
  5. Step 5: Solve for x
    x = 547,782.17/817.21
  6. Step 6: Final answer
    x = 670.31

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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.