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Finding the Fourth Proportional to 30.65, 42.30 and 21.92

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Solution

The fourth proportional to 30.65, 42.30 and 21.92 is: 30.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.65 : 42.30 = 21.92 : x
  2. Step 2: Convert to fraction form
    30.65/42.30 = 21.92/x
  3. Step 3: Cross multiply
    30.65x = 42.30 × 21.92
  4. Step 4: Simplify right side
    30.65x = 927.22
  5. Step 5: Solve for x
    x = 927.22/30.65
  6. Step 6: Final answer
    x = 30.25

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.