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Finding the Fourth Proportional to 128.01, 191.25 and 121.35

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Solution

The fourth proportional to 128.01, 191.25 and 121.35 is: 181.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.01 : 191.25 = 121.35 : x
  2. Step 2: Convert to fraction form
    128.01/191.25 = 121.35/x
  3. Step 3: Cross multiply
    128.01x = 191.25 × 121.35
  4. Step 4: Simplify right side
    128.01x = 23,208.19
  5. Step 5: Solve for x
    x = 23,208.19/128.01
  6. Step 6: Final answer
    x = 181.30

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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.