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Finding the Fourth Proportional to 993.70, 1,371.56 and 639.87

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Solution

The fourth proportional to 993.70, 1,371.56 and 639.87 is: 883.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    993.70 : 1,371.56 = 639.87 : x
  2. Step 2: Convert to fraction form
    993.70/1,371.56 = 639.87/x
  3. Step 3: Cross multiply
    993.70x = 1,371.56 × 639.87
  4. Step 4: Simplify right side
    993.70x = 877,620.10
  5. Step 5: Solve for x
    x = 877,620.10/993.70
  6. Step 6: Final answer
    x = 883.18

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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.