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Finding the Fourth Proportional to 20.99, 31.43 and 20.50

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Solution

The fourth proportional to 20.99, 31.43 and 20.50 is: 30.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.99 : 31.43 = 20.50 : x
  2. Step 2: Convert to fraction form
    20.99/31.43 = 20.50/x
  3. Step 3: Cross multiply
    20.99x = 31.43 × 20.50
  4. Step 4: Simplify right side
    20.99x = 644.32
  5. Step 5: Solve for x
    x = 644.32/20.99
  6. Step 6: Final answer
    x = 30.70

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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.