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Finding the Fourth Proportional to 30.76, 42.74 and 30.38

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Solution

The fourth proportional to 30.76, 42.74 and 30.38 is: 42.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.76 : 42.74 = 30.38 : x
  2. Step 2: Convert to fraction form
    30.76/42.74 = 30.38/x
  3. Step 3: Cross multiply
    30.76x = 42.74 × 30.38
  4. Step 4: Simplify right side
    30.76x = 1,298.23
  5. Step 5: Solve for x
    x = 1,298.23/30.76
  6. Step 6: Final answer
    x = 42.21

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.