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Finding the Fourth Proportional to 28.70, 39.58 and 20.94

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Solution

The fourth proportional to 28.70, 39.58 and 20.94 is: 28.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.70 : 39.58 = 20.94 : x
  2. Step 2: Convert to fraction form
    28.70/39.58 = 20.94/x
  3. Step 3: Cross multiply
    28.70x = 39.58 × 20.94
  4. Step 4: Simplify right side
    28.70x = 828.81
  5. Step 5: Solve for x
    x = 828.81/28.70
  6. Step 6: Final answer
    x = 28.88

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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.