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Finding the Fourth Proportional to 165.78, 228.29 and 128.87

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Solution

The fourth proportional to 165.78, 228.29 and 128.87 is: 177.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    165.78 : 228.29 = 128.87 : x
  2. Step 2: Convert to fraction form
    165.78/228.29 = 128.87/x
  3. Step 3: Cross multiply
    165.78x = 228.29 × 128.87
  4. Step 4: Simplify right side
    165.78x = 29,421.17
  5. Step 5: Solve for x
    x = 29,421.17/165.78
  6. Step 6: Final answer
    x = 177.47

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.