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Finding the Fourth Proportional to 134.65, 201.42 and 85.78

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Solution

The fourth proportional to 134.65, 201.42 and 85.78 is: 128.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    134.65 : 201.42 = 85.78 : x
  2. Step 2: Convert to fraction form
    134.65/201.42 = 85.78/x
  3. Step 3: Cross multiply
    134.65x = 201.42 × 85.78
  4. Step 4: Simplify right side
    134.65x = 17,277.81
  5. Step 5: Solve for x
    x = 17,277.81/134.65
  6. Step 6: Final answer
    x = 128.32

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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.