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Finding the Fourth Proportional to 512.78, 769.18 and 128.03

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Solution

The fourth proportional to 512.78, 769.18 and 128.03 is: 192.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    512.78 : 769.18 = 128.03 : x
  2. Step 2: Convert to fraction form
    512.78/769.18 = 128.03/x
  3. Step 3: Cross multiply
    512.78x = 769.18 × 128.03
  4. Step 4: Simplify right side
    512.78x = 98,478.12
  5. Step 5: Solve for x
    x = 98,478.12/512.78
  6. Step 6: Final answer
    x = 192.05

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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.