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Finding the Fourth Proportional to 989.21, 1,366.12 and 765.96

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Solution

The fourth proportional to 989.21, 1,366.12 and 765.96 is: 1,057.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.21 : 1,366.12 = 765.96 : x
  2. Step 2: Convert to fraction form
    989.21/1,366.12 = 765.96/x
  3. Step 3: Cross multiply
    989.21x = 1,366.12 × 765.96
  4. Step 4: Simplify right side
    989.21x = 1,046,384.80
  5. Step 5: Solve for x
    x = 1,046,384.80/989.21
  6. Step 6: Final answer
    x = 1,057.80

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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.