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Finding the Fourth Proportional to 66.45, 90.96 and 65.28

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Solution

The fourth proportional to 66.45, 90.96 and 65.28 is: 89.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.45 : 90.96 = 65.28 : x
  2. Step 2: Convert to fraction form
    66.45/90.96 = 65.28/x
  3. Step 3: Cross multiply
    66.45x = 90.96 × 65.28
  4. Step 4: Simplify right side
    66.45x = 5,937.87
  5. Step 5: Solve for x
    x = 5,937.87/66.45
  6. Step 6: Final answer
    x = 89.36

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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.