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Finding the Fourth Proportional to 712.85, 982.79 and 639.95

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Solution

The fourth proportional to 712.85, 982.79 and 639.95 is: 882.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.85 : 982.79 = 639.95 : x
  2. Step 2: Convert to fraction form
    712.85/982.79 = 639.95/x
  3. Step 3: Cross multiply
    712.85x = 982.79 × 639.95
  4. Step 4: Simplify right side
    712.85x = 628,935.72
  5. Step 5: Solve for x
    x = 628,935.72/712.85
  6. Step 6: Final answer
    x = 882.28

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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.