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Finding the Fourth Proportional to 30.45, 42.01 and 21.12

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Solution

The fourth proportional to 30.45, 42.01 and 21.12 is: 29.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.45 : 42.01 = 21.12 : x
  2. Step 2: Convert to fraction form
    30.45/42.01 = 21.12/x
  3. Step 3: Cross multiply
    30.45x = 42.01 × 21.12
  4. Step 4: Simplify right side
    30.45x = 887.40
  5. Step 5: Solve for x
    x = 887.40/30.45
  6. Step 6: Final answer
    x = 29.14

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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.