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Finding the Fourth Proportional to 344.78, 516.86 and 128.21

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Solution

The fourth proportional to 344.78, 516.86 and 128.21 is: 192.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    344.78 : 516.86 = 128.21 : x
  2. Step 2: Convert to fraction form
    344.78/516.86 = 128.21/x
  3. Step 3: Cross multiply
    344.78x = 516.86 × 128.21
  4. Step 4: Simplify right side
    344.78x = 66,263.40
  5. Step 5: Solve for x
    x = 66,263.40/344.78
  6. Step 6: Final answer
    x = 192.19

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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.