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Finding the Fourth Proportional to 981.30, 1,350.60 and 861

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Solution

The fourth proportional to 981.30, 1,350.60 and 861 is: 1,185.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.30 : 1,350.60 = 861 : x
  2. Step 2: Convert to fraction form
    981.30/1,350.60 = 861/x
  3. Step 3: Cross multiply
    981.30x = 1,350.60 × 861
  4. Step 4: Simplify right side
    981.30x = 1,162,866.60
  5. Step 5: Solve for x
    x = 1,162,866.60/981.30
  6. Step 6: Final answer
    x = 1,185.03

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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.