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Finding the Fourth Proportional to 990.29, 1,366.61 and 641.59

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Solution

The fourth proportional to 990.29, 1,366.61 and 641.59 is: 885.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.29 : 1,366.61 = 641.59 : x
  2. Step 2: Convert to fraction form
    990.29/1,366.61 = 641.59/x
  3. Step 3: Cross multiply
    990.29x = 1,366.61 × 641.59
  4. Step 4: Simplify right side
    990.29x = 876,796.69
  5. Step 5: Solve for x
    x = 876,796.69/990.29
  6. Step 6: Final answer
    x = 885.39

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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.