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Finding the Fourth Proportional to 990.90, 1,367.49 and 571.39

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Solution

The fourth proportional to 990.90, 1,367.49 and 571.39 is: 788.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.90 : 1,367.49 = 571.39 : x
  2. Step 2: Convert to fraction form
    990.90/1,367.49 = 571.39/x
  3. Step 3: Cross multiply
    990.90x = 1,367.49 × 571.39
  4. Step 4: Simplify right side
    990.90x = 781,370.11
  5. Step 5: Solve for x
    x = 781,370.11/990.90
  6. Step 6: Final answer
    x = 788.55

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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.