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Finding the Fourth Proportional to 85.45, 128.16 and 36.69

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Solution

The fourth proportional to 85.45, 128.16 and 36.69 is: 55.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.45 : 128.16 = 36.69 : x
  2. Step 2: Convert to fraction form
    85.45/128.16 = 36.69/x
  3. Step 3: Cross multiply
    85.45x = 128.16 × 36.69
  4. Step 4: Simplify right side
    85.45x = 4,701.61
  5. Step 5: Solve for x
    x = 4,701.61/85.45
  6. Step 6: Final answer
    x = 55.02

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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.