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Finding the Fourth Proportional to 918.72, 1,266.36 and 639.27

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Solution

The fourth proportional to 918.72, 1,266.36 and 639.27 is: 881.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.72 : 1,266.36 = 639.27 : x
  2. Step 2: Convert to fraction form
    918.72/1,266.36 = 639.27/x
  3. Step 3: Cross multiply
    918.72x = 1,266.36 × 639.27
  4. Step 4: Simplify right side
    918.72x = 809,545.96
  5. Step 5: Solve for x
    x = 809,545.96/918.72
  6. Step 6: Final answer
    x = 881.17

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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.