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Finding the Fourth Proportional to 142.80, 197.10 and 128.22

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Solution

The fourth proportional to 142.80, 197.10 and 128.22 is: 176.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.80 : 197.10 = 128.22 : x
  2. Step 2: Convert to fraction form
    142.80/197.10 = 128.22/x
  3. Step 3: Cross multiply
    142.80x = 197.10 × 128.22
  4. Step 4: Simplify right side
    142.80x = 25,272.16
  5. Step 5: Solve for x
    x = 25,272.16/142.80
  6. Step 6: Final answer
    x = 176.98

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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.