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Finding the Fourth Proportional to 345.61, 518.20 and 128.93

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Solution

The fourth proportional to 345.61, 518.20 and 128.93 is: 193.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    345.61 : 518.20 = 128.93 : x
  2. Step 2: Convert to fraction form
    345.61/518.20 = 128.93/x
  3. Step 3: Cross multiply
    345.61x = 518.20 × 128.93
  4. Step 4: Simplify right side
    345.61x = 66,811.20
  5. Step 5: Solve for x
    x = 66,811.20/345.61
  6. Step 6: Final answer
    x = 193.32

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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.