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Finding the Fourth Proportional to 85.73, 128.40 and 53.25

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Solution

The fourth proportional to 85.73, 128.40 and 53.25 is: 79.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.73 : 128.40 = 53.25 : x
  2. Step 2: Convert to fraction form
    85.73/128.40 = 53.25/x
  3. Step 3: Cross multiply
    85.73x = 128.40 × 53.25
  4. Step 4: Simplify right side
    85.73x = 6,837.30
  5. Step 5: Solve for x
    x = 6,837.30/85.73
  6. Step 6: Final answer
    x = 79.75

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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.