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Finding the Fourth Proportional to 979.43, 1,351.67 and 811.31

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Solution

The fourth proportional to 979.43, 1,351.67 and 811.31 is: 1,119.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.43 : 1,351.67 = 811.31 : x
  2. Step 2: Convert to fraction form
    979.43/1,351.67 = 811.31/x
  3. Step 3: Cross multiply
    979.43x = 1,351.67 × 811.31
  4. Step 4: Simplify right side
    979.43x = 1,096,612.57
  5. Step 5: Solve for x
    x = 1,096,612.57/979.43
  6. Step 6: Final answer
    x = 1,119.65

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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.