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Finding the Fourth Proportional to 128.39, 177.18 and 79.26

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Solution

The fourth proportional to 128.39, 177.18 and 79.26 is: 109.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.39 : 177.18 = 79.26 : x
  2. Step 2: Convert to fraction form
    128.39/177.18 = 79.26/x
  3. Step 3: Cross multiply
    128.39x = 177.18 × 79.26
  4. Step 4: Simplify right side
    128.39x = 14,043.29
  5. Step 5: Solve for x
    x = 14,043.29/128.39
  6. Step 6: Final answer
    x = 109.38

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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.