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Finding the Fourth Proportional to 30.68, 42.63 and 30.31

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Solution

The fourth proportional to 30.68, 42.63 and 30.31 is: 42.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.68 : 42.63 = 30.31 : x
  2. Step 2: Convert to fraction form
    30.68/42.63 = 30.31/x
  3. Step 3: Cross multiply
    30.68x = 42.63 × 30.31
  4. Step 4: Simplify right side
    30.68x = 1,292.12
  5. Step 5: Solve for x
    x = 1,292.12/30.68
  6. Step 6: Final answer
    x = 42.12

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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.