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Finding the Fourth Proportional to 128.84, 177.74 and 120.13

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Solution

The fourth proportional to 128.84, 177.74 and 120.13 is: 165.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.84 : 177.74 = 120.13 : x
  2. Step 2: Convert to fraction form
    128.84/177.74 = 120.13/x
  3. Step 3: Cross multiply
    128.84x = 177.74 × 120.13
  4. Step 4: Simplify right side
    128.84x = 21,351.91
  5. Step 5: Solve for x
    x = 21,351.91/128.84
  6. Step 6: Final answer
    x = 165.72

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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.