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Finding the Fourth Proportional to 384.78, 577.11 and 128.28

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Solution

The fourth proportional to 384.78, 577.11 and 128.28 is: 192.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    384.78 : 577.11 = 128.28 : x
  2. Step 2: Convert to fraction form
    384.78/577.11 = 128.28/x
  3. Step 3: Cross multiply
    384.78x = 577.11 × 128.28
  4. Step 4: Simplify right side
    384.78x = 74,031.67
  5. Step 5: Solve for x
    x = 74,031.67/384.78
  6. Step 6: Final answer
    x = 192.40

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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.