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Finding the Fourth Proportional to 991.45, 1,368.35 and 571.72

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Solution

The fourth proportional to 991.45, 1,368.35 and 571.72 is: 789.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.45 : 1,368.35 = 571.72 : x
  2. Step 2: Convert to fraction form
    991.45/1,368.35 = 571.72/x
  3. Step 3: Cross multiply
    991.45x = 1,368.35 × 571.72
  4. Step 4: Simplify right side
    991.45x = 782,313.06
  5. Step 5: Solve for x
    x = 782,313.06/991.45
  6. Step 6: Final answer
    x = 789.06

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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.