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Finding the Fourth Proportional to 985.31, 1,484.73 and 815.78

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Solution

The fourth proportional to 985.31, 1,484.73 and 815.78 is: 1,229.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.31 : 1,484.73 = 815.78 : x
  2. Step 2: Convert to fraction form
    985.31/1,484.73 = 815.78/x
  3. Step 3: Cross multiply
    985.31x = 1,484.73 × 815.78
  4. Step 4: Simplify right side
    985.31x = 1,211,216.75
  5. Step 5: Solve for x
    x = 1,211,216.75/985.31
  6. Step 6: Final answer
    x = 1,229.27

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.