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Finding the Fourth Proportional to 1,397.85, 1,929.79 and 979.48

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Solution

The fourth proportional to 1,397.85, 1,929.79 and 979.48 is: 1,352.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,397.85 : 1,929.79 = 979.48 : x
  2. Step 2: Convert to fraction form
    1,397.85/1,929.79 = 979.48/x
  3. Step 3: Cross multiply
    1,397.85x = 1,929.79 × 979.48
  4. Step 4: Simplify right side
    1,397.85x = 1,890,190.71
  5. Step 5: Solve for x
    x = 1,890,190.71/1,397.85
  6. Step 6: Final answer
    x = 1,352.22

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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.