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Finding the Fourth Proportional to 989.36, 1,365.08 and 639.98

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Solution

The fourth proportional to 989.36, 1,365.08 and 639.98 is: 883.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.36 : 1,365.08 = 639.98 : x
  2. Step 2: Convert to fraction form
    989.36/1,365.08 = 639.98/x
  3. Step 3: Cross multiply
    989.36x = 1,365.08 × 639.98
  4. Step 4: Simplify right side
    989.36x = 873,623.90
  5. Step 5: Solve for x
    x = 873,623.90/989.36
  6. Step 6: Final answer
    x = 883.02

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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.