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Finding the Fourth Proportional to 30.81, 42.21 and 30.36

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Solution

The fourth proportional to 30.81, 42.21 and 30.36 is: 41.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.81 : 42.21 = 30.36 : x
  2. Step 2: Convert to fraction form
    30.81/42.21 = 30.36/x
  3. Step 3: Cross multiply
    30.81x = 42.21 × 30.36
  4. Step 4: Simplify right side
    30.81x = 1,281.50
  5. Step 5: Solve for x
    x = 1,281.50/30.81
  6. Step 6: Final answer
    x = 41.59

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.