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Finding the Fourth Proportional to 128.58, 192.89 and 74.53

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Solution

The fourth proportional to 128.58, 192.89 and 74.53 is: 111.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.58 : 192.89 = 74.53 : x
  2. Step 2: Convert to fraction form
    128.58/192.89 = 74.53/x
  3. Step 3: Cross multiply
    128.58x = 192.89 × 74.53
  4. Step 4: Simplify right side
    128.58x = 14,376.09
  5. Step 5: Solve for x
    x = 14,376.09/128.58
  6. Step 6: Final answer
    x = 111.81

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.