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Finding the Fourth Proportional to 989.64, 1,479.96 and 742.98

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Solution

The fourth proportional to 989.64, 1,479.96 and 742.98 is: 1,111.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.64 : 1,479.96 = 742.98 : x
  2. Step 2: Convert to fraction form
    989.64/1,479.96 = 742.98/x
  3. Step 3: Cross multiply
    989.64x = 1,479.96 × 742.98
  4. Step 4: Simplify right side
    989.64x = 1,099,580.68
  5. Step 5: Solve for x
    x = 1,099,580.68/989.64
  6. Step 6: Final answer
    x = 1,111.09

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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.