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Finding the Fourth Proportional to 991.91, 1,369.01 and 638.27

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Solution

The fourth proportional to 991.91, 1,369.01 and 638.27 is: 880.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.91 : 1,369.01 = 638.27 : x
  2. Step 2: Convert to fraction form
    991.91/1,369.01 = 638.27/x
  3. Step 3: Cross multiply
    991.91x = 1,369.01 × 638.27
  4. Step 4: Simplify right side
    991.91x = 873,803.03
  5. Step 5: Solve for x
    x = 873,803.03/991.91
  6. Step 6: Final answer
    x = 880.93

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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.