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Finding the Fourth Proportional to 65.48, 90.39 and 42.20

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Solution

The fourth proportional to 65.48, 90.39 and 42.20 is: 58.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.48 : 90.39 = 42.20 : x
  2. Step 2: Convert to fraction form
    65.48/90.39 = 42.20/x
  3. Step 3: Cross multiply
    65.48x = 90.39 × 42.20
  4. Step 4: Simplify right side
    65.48x = 3,814.46
  5. Step 5: Solve for x
    x = 3,814.46/65.48
  6. Step 6: Final answer
    x = 58.25

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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.