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Finding the Fourth Proportional to 21.13, 31.55 and 18.30

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Solution

The fourth proportional to 21.13, 31.55 and 18.30 is: 27.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.13 : 31.55 = 18.30 : x
  2. Step 2: Convert to fraction form
    21.13/31.55 = 18.30/x
  3. Step 3: Cross multiply
    21.13x = 31.55 × 18.30
  4. Step 4: Simplify right side
    21.13x = 577.37
  5. Step 5: Solve for x
    x = 577.37/21.13
  6. Step 6: Final answer
    x = 27.32

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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.