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Finding the Fourth Proportional to 20, 29.98 and 12.78

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Solution

The fourth proportional to 20, 29.98 and 12.78 is: 19.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    20 : 29.98 = 12.78 : x
  2. Step 2: Convert to fraction form
    20/29.98 = 12.78/x
  3. Step 3: Cross multiply
    20x = 29.98 × 12.78
  4. Step 4: Simplify right side
    20x = 383.14
  5. Step 5: Solve for x
    x = 383.14/20
  6. Step 6: Final answer
    x = 19.16

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.