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Finding the Fourth Proportional to 85.72, 118.52 and 65.11

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Solution

The fourth proportional to 85.72, 118.52 and 65.11 is: 90.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.72 : 118.52 = 65.11 : x
  2. Step 2: Convert to fraction form
    85.72/118.52 = 65.11/x
  3. Step 3: Cross multiply
    85.72x = 118.52 × 65.11
  4. Step 4: Simplify right side
    85.72x = 7,716.84
  5. Step 5: Solve for x
    x = 7,716.84/85.72
  6. Step 6: Final answer
    x = 90.02

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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.