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Finding the Fourth Proportional to 991.47, 1,368.22 and 571.90

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Solution

The fourth proportional to 991.47, 1,368.22 and 571.90 is: 789.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.47 : 1,368.22 = 571.90 : x
  2. Step 2: Convert to fraction form
    991.47/1,368.22 = 571.90/x
  3. Step 3: Cross multiply
    991.47x = 1,368.22 × 571.90
  4. Step 4: Simplify right side
    991.47x = 782,485.02
  5. Step 5: Solve for x
    x = 782,485.02/991.47
  6. Step 6: Final answer
    x = 789.22

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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.