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Finding the Fourth Proportional to 66.12, 90.75 and 63.12

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Solution

The fourth proportional to 66.12, 90.75 and 63.12 is: 86.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.12 : 90.75 = 63.12 : x
  2. Step 2: Convert to fraction form
    66.12/90.75 = 63.12/x
  3. Step 3: Cross multiply
    66.12x = 90.75 × 63.12
  4. Step 4: Simplify right side
    66.12x = 5,728.14
  5. Step 5: Solve for x
    x = 5,728.14/66.12
  6. Step 6: Final answer
    x = 86.63

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.