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Finding the Fourth Proportional to 918.42, 1,267 and 639.32

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Solution

The fourth proportional to 918.42, 1,267 and 639.32 is: 881.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.42 : 1,267 = 639.32 : x
  2. Step 2: Convert to fraction form
    918.42/1,267 = 639.32/x
  3. Step 3: Cross multiply
    918.42x = 1,267 × 639.32
  4. Step 4: Simplify right side
    918.42x = 810,018.44
  5. Step 5: Solve for x
    x = 810,018.44/918.42
  6. Step 6: Final answer
    x = 881.97

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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.