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Finding the Fourth Proportional to 991.31, 1,487.07 and 342.05

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Solution

The fourth proportional to 991.31, 1,487.07 and 342.05 is: 513.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.31 : 1,487.07 = 342.05 : x
  2. Step 2: Convert to fraction form
    991.31/1,487.07 = 342.05/x
  3. Step 3: Cross multiply
    991.31x = 1,487.07 × 342.05
  4. Step 4: Simplify right side
    991.31x = 508,644.86
  5. Step 5: Solve for x
    x = 508,644.86/991.31
  6. Step 6: Final answer
    x = 513.10

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.