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Finding the Fourth Proportional to 939.15, 1,299.29 and 905.45

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Solution

The fourth proportional to 939.15, 1,299.29 and 905.45 is: 1,252.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.15 : 1,299.29 = 905.45 : x
  2. Step 2: Convert to fraction form
    939.15/1,299.29 = 905.45/x
  3. Step 3: Cross multiply
    939.15x = 1,299.29 × 905.45
  4. Step 4: Simplify right side
    939.15x = 1,176,431.11
  5. Step 5: Solve for x
    x = 1,176,431.11/939.15
  6. Step 6: Final answer
    x = 1,252.66

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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.