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Finding the Fourth Proportional to 1,321.09, 1,981.64 and 347.19

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Solution

The fourth proportional to 1,321.09, 1,981.64 and 347.19 is: 520.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.09 : 1,981.64 = 347.19 : x
  2. Step 2: Convert to fraction form
    1,321.09/1,981.64 = 347.19/x
  3. Step 3: Cross multiply
    1,321.09x = 1,981.64 × 347.19
  4. Step 4: Simplify right side
    1,321.09x = 688,005.59
  5. Step 5: Solve for x
    x = 688,005.59/1,321.09
  6. Step 6: Final answer
    x = 520.79

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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.