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Finding the Fourth Proportional to 21.02, 31.54 and 10.87

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Solution

The fourth proportional to 21.02, 31.54 and 10.87 is: 16.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.02 : 31.54 = 10.87 : x
  2. Step 2: Convert to fraction form
    21.02/31.54 = 10.87/x
  3. Step 3: Cross multiply
    21.02x = 31.54 × 10.87
  4. Step 4: Simplify right side
    21.02x = 342.89
  5. Step 5: Solve for x
    x = 342.89/21.02
  6. Step 6: Final answer
    x = 16.31

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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.