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Finding the Fourth Proportional to 128.35, 177.20 and 89.23

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Solution

The fourth proportional to 128.35, 177.20 and 89.23 is: 123.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.35 : 177.20 = 89.23 : x
  2. Step 2: Convert to fraction form
    128.35/177.20 = 89.23/x
  3. Step 3: Cross multiply
    128.35x = 177.20 × 89.23
  4. Step 4: Simplify right side
    128.35x = 15,811.56
  5. Step 5: Solve for x
    x = 15,811.56/128.35
  6. Step 6: Final answer
    x = 123.19

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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.