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Finding the Fourth Proportional to 128.69, 177.60 and 73.42

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Solution

The fourth proportional to 128.69, 177.60 and 73.42 is: 101.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.69 : 177.60 = 73.42 : x
  2. Step 2: Convert to fraction form
    128.69/177.60 = 73.42/x
  3. Step 3: Cross multiply
    128.69x = 177.60 × 73.42
  4. Step 4: Simplify right side
    128.69x = 13,039.21
  5. Step 5: Solve for x
    x = 13,039.21/128.69
  6. Step 6: Final answer
    x = 101.32

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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.