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Finding the Fourth Proportional to 61.28, 91.80 and 30.81

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Solution

The fourth proportional to 61.28, 91.80 and 30.81 is: 46.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.28 : 91.80 = 30.81 : x
  2. Step 2: Convert to fraction form
    61.28/91.80 = 30.81/x
  3. Step 3: Cross multiply
    61.28x = 91.80 × 30.81
  4. Step 4: Simplify right side
    61.28x = 2,828.36
  5. Step 5: Solve for x
    x = 2,828.36/61.28
  6. Step 6: Final answer
    x = 46.15

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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.