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Finding the Fourth Proportional to 28.65, 42.90 and 25.80

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Solution

The fourth proportional to 28.65, 42.90 and 25.80 is: 38.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.65 : 42.90 = 25.80 : x
  2. Step 2: Convert to fraction form
    28.65/42.90 = 25.80/x
  3. Step 3: Cross multiply
    28.65x = 42.90 × 25.80
  4. Step 4: Simplify right side
    28.65x = 1,106.82
  5. Step 5: Solve for x
    x = 1,106.82/28.65
  6. Step 6: Final answer
    x = 38.63

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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.