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Finding the Fourth Proportional to 345.03, 517.21 and 128.56

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Solution

The fourth proportional to 345.03, 517.21 and 128.56 is: 192.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    345.03 : 517.21 = 128.56 : x
  2. Step 2: Convert to fraction form
    345.03/517.21 = 128.56/x
  3. Step 3: Cross multiply
    345.03x = 517.21 × 128.56
  4. Step 4: Simplify right side
    345.03x = 66,492.52
  5. Step 5: Solve for x
    x = 66,492.52/345.03
  6. Step 6: Final answer
    x = 192.72

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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.