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Finding the Fourth Proportional to 85.49, 128.19 and 30.64

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Solution

The fourth proportional to 85.49, 128.19 and 30.64 is: 45.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.49 : 128.19 = 30.64 : x
  2. Step 2: Convert to fraction form
    85.49/128.19 = 30.64/x
  3. Step 3: Cross multiply
    85.49x = 128.19 × 30.64
  4. Step 4: Simplify right side
    85.49x = 3,927.33
  5. Step 5: Solve for x
    x = 3,927.33/85.49
  6. Step 6: Final answer
    x = 45.94

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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.