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Finding the Fourth Proportional to 985.31, 1,359.80 and 571.31

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Solution

The fourth proportional to 985.31, 1,359.80 and 571.31 is: 788.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.31 : 1,359.80 = 571.31 : x
  2. Step 2: Convert to fraction form
    985.31/1,359.80 = 571.31/x
  3. Step 3: Cross multiply
    985.31x = 1,359.80 × 571.31
  4. Step 4: Simplify right side
    985.31x = 776,864.48
  5. Step 5: Solve for x
    x = 776,864.48/985.31
  6. Step 6: Final answer
    x = 788.45

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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.