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Finding the Fourth Proportional to 990.71, 1,486.38 and 442.79

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Solution

The fourth proportional to 990.71, 1,486.38 and 442.79 is: 664.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.71 : 1,486.38 = 442.79 : x
  2. Step 2: Convert to fraction form
    990.71/1,486.38 = 442.79/x
  3. Step 3: Cross multiply
    990.71x = 1,486.38 × 442.79
  4. Step 4: Simplify right side
    990.71x = 658,146.77
  5. Step 5: Solve for x
    x = 658,146.77/990.71
  6. Step 6: Final answer
    x = 664.32

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.