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Finding the Fourth Proportional to 65.43, 90.21 and 40.86

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Solution

The fourth proportional to 65.43, 90.21 and 40.86 is: 56.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.43 : 90.21 = 40.86 : x
  2. Step 2: Convert to fraction form
    65.43/90.21 = 40.86/x
  3. Step 3: Cross multiply
    65.43x = 90.21 × 40.86
  4. Step 4: Simplify right side
    65.43x = 3,685.98
  5. Step 5: Solve for x
    x = 3,685.98/65.43
  6. Step 6: Final answer
    x = 56.33

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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.