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Finding the Fourth Proportional to 712.90, 983.98 and 639.09

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Solution

The fourth proportional to 712.90, 983.98 and 639.09 is: 882.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.90 : 983.98 = 639.09 : x
  2. Step 2: Convert to fraction form
    712.90/983.98 = 639.09/x
  3. Step 3: Cross multiply
    712.90x = 983.98 × 639.09
  4. Step 4: Simplify right side
    712.90x = 628,851.78
  5. Step 5: Solve for x
    x = 628,851.78/712.90
  6. Step 6: Final answer
    x = 882.10

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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.