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Finding the Fourth Proportional to 30.96, 42.68 and 21.77

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Solution

The fourth proportional to 30.96, 42.68 and 21.77 is: 30.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.96 : 42.68 = 21.77 : x
  2. Step 2: Convert to fraction form
    30.96/42.68 = 21.77/x
  3. Step 3: Cross multiply
    30.96x = 42.68 × 21.77
  4. Step 4: Simplify right side
    30.96x = 929.30
  5. Step 5: Solve for x
    x = 929.30/30.96
  6. Step 6: Final answer
    x = 30.01

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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.