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Finding the Fourth Proportional to 13, 19.42 and 12.28

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Solution

The fourth proportional to 13, 19.42 and 12.28 is: 18.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    13 : 19.42 = 12.28 : x
  2. Step 2: Convert to fraction form
    13/19.42 = 12.28/x
  3. Step 3: Cross multiply
    13x = 19.42 × 12.28
  4. Step 4: Simplify right side
    13x = 238.48
  5. Step 5: Solve for x
    x = 238.48/13
  6. Step 6: Final answer
    x = 18.34

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.