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Finding the Fourth Proportional to 991.83, 1,487.43 and 261.32

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Solution

The fourth proportional to 991.83, 1,487.43 and 261.32 is: 391.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.83 : 1,487.43 = 261.32 : x
  2. Step 2: Convert to fraction form
    991.83/1,487.43 = 261.32/x
  3. Step 3: Cross multiply
    991.83x = 1,487.43 × 261.32
  4. Step 4: Simplify right side
    991.83x = 388,687.77
  5. Step 5: Solve for x
    x = 388,687.77/991.83
  6. Step 6: Final answer
    x = 391.89

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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.