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Finding the Fourth Proportional to 28, 42 and 8.74

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Solution

The fourth proportional to 28, 42 and 8.74 is: 13.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    28 : 42 = 8.74 : x
  2. Step 2: Convert to fraction form
    28/42 = 8.74/x
  3. Step 3: Cross multiply
    28x = 42 × 8.74
  4. Step 4: Simplify right side
    28x = 367.08
  5. Step 5: Solve for x
    x = 367.08/28
  6. Step 6: Final answer
    x = 13.11

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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.