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Finding the Fourth Proportional to 21.64, 29.87 and 13.45

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Solution

The fourth proportional to 21.64, 29.87 and 13.45 is: 18.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.64 : 29.87 = 13.45 : x
  2. Step 2: Convert to fraction form
    21.64/29.87 = 13.45/x
  3. Step 3: Cross multiply
    21.64x = 29.87 × 13.45
  4. Step 4: Simplify right side
    21.64x = 401.85
  5. Step 5: Solve for x
    x = 401.85/21.64
  6. Step 6: Final answer
    x = 18.57

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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.