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Finding the Fourth Proportional to 65.81, 98.72 and 20.16

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Solution

The fourth proportional to 65.81, 98.72 and 20.16 is: 30.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.81 : 98.72 = 20.16 : x
  2. Step 2: Convert to fraction form
    65.81/98.72 = 20.16/x
  3. Step 3: Cross multiply
    65.81x = 98.72 × 20.16
  4. Step 4: Simplify right side
    65.81x = 1,990.20
  5. Step 5: Solve for x
    x = 1,990.20/65.81
  6. Step 6: Final answer
    x = 30.24

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.