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Finding the Fourth Proportional to 30.57, 42.18 and 19.68

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Solution

The fourth proportional to 30.57, 42.18 and 19.68 is: 27.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.57 : 42.18 = 19.68 : x
  2. Step 2: Convert to fraction form
    30.57/42.18 = 19.68/x
  3. Step 3: Cross multiply
    30.57x = 42.18 × 19.68
  4. Step 4: Simplify right side
    30.57x = 830.10
  5. Step 5: Solve for x
    x = 830.10/30.57
  6. Step 6: Final answer
    x = 27.15

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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.