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Finding the Fourth Proportional to 128.69, 177.59 and 76.24

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Solution

The fourth proportional to 128.69, 177.59 and 76.24 is: 105.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.69 : 177.59 = 76.24 : x
  2. Step 2: Convert to fraction form
    128.69/177.59 = 76.24/x
  3. Step 3: Cross multiply
    128.69x = 177.59 × 76.24
  4. Step 4: Simplify right side
    128.69x = 13,539.87
  5. Step 5: Solve for x
    x = 13,539.87/128.69
  6. Step 6: Final answer
    x = 105.21

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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.