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Finding the Fourth Proportional to 128.65, 177.42 and 84.37

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Solution

The fourth proportional to 128.65, 177.42 and 84.37 is: 116.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.65 : 177.42 = 84.37 : x
  2. Step 2: Convert to fraction form
    128.65/177.42 = 84.37/x
  3. Step 3: Cross multiply
    128.65x = 177.42 × 84.37
  4. Step 4: Simplify right side
    128.65x = 14,968.93
  5. Step 5: Solve for x
    x = 14,968.93/128.65
  6. Step 6: Final answer
    x = 116.35

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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.