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Finding the Fourth Proportional to 143.79, 214.61 and 128.44

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Solution

The fourth proportional to 143.79, 214.61 and 128.44 is: 191.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.79 : 214.61 = 128.44 : x
  2. Step 2: Convert to fraction form
    143.79/214.61 = 128.44/x
  3. Step 3: Cross multiply
    143.79x = 214.61 × 128.44
  4. Step 4: Simplify right side
    143.79x = 27,564.51
  5. Step 5: Solve for x
    x = 27,564.51/143.79
  6. Step 6: Final answer
    x = 191.70

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.