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Finding the Fourth Proportional to 65.45, 90.38 and 42.18

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Solution

The fourth proportional to 65.45, 90.38 and 42.18 is: 58.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.45 : 90.38 = 42.18 : x
  2. Step 2: Convert to fraction form
    65.45/90.38 = 42.18/x
  3. Step 3: Cross multiply
    65.45x = 90.38 × 42.18
  4. Step 4: Simplify right side
    65.45x = 3,811.84
  5. Step 5: Solve for x
    x = 3,811.84/65.45
  6. Step 6: Final answer
    x = 58.24

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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.