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Finding the Fourth Proportional to 347.81, 521.66 and 128.40

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Solution

The fourth proportional to 347.81, 521.66 and 128.40 is: 192.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    347.81 : 521.66 = 128.40 : x
  2. Step 2: Convert to fraction form
    347.81/521.66 = 128.40/x
  3. Step 3: Cross multiply
    347.81x = 521.66 × 128.40
  4. Step 4: Simplify right side
    347.81x = 66,982.46
  5. Step 5: Solve for x
    x = 66,982.46/347.81
  6. Step 6: Final answer
    x = 192.58

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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.