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Finding the Fourth Proportional to 1,321.23, 1,981.78 and 347.31

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Solution

The fourth proportional to 1,321.23, 1,981.78 and 347.31 is: 520.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.23 : 1,981.78 = 347.31 : x
  2. Step 2: Convert to fraction form
    1,321.23/1,981.78 = 347.31/x
  3. Step 3: Cross multiply
    1,321.23x = 1,981.78 × 347.31
  4. Step 4: Simplify right side
    1,321.23x = 688,292.01
  5. Step 5: Solve for x
    x = 688,292.01/1,321.23
  6. Step 6: Final answer
    x = 520.95

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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.