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Finding the Fourth Proportional to 142.55, 196.15 and 128.75

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Solution

The fourth proportional to 142.55, 196.15 and 128.75 is: 177.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.55 : 196.15 = 128.75 : x
  2. Step 2: Convert to fraction form
    142.55/196.15 = 128.75/x
  3. Step 3: Cross multiply
    142.55x = 196.15 × 128.75
  4. Step 4: Simplify right side
    142.55x = 25,254.31
  5. Step 5: Solve for x
    x = 25,254.31/142.55
  6. Step 6: Final answer
    x = 177.16

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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.