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Finding the Fourth Proportional to 28.80, 39.84 and 28.20

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Solution

The fourth proportional to 28.80, 39.84 and 28.20 is: 39.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.80 : 39.84 = 28.20 : x
  2. Step 2: Convert to fraction form
    28.80/39.84 = 28.20/x
  3. Step 3: Cross multiply
    28.80x = 39.84 × 28.20
  4. Step 4: Simplify right side
    28.80x = 1,123.49
  5. Step 5: Solve for x
    x = 1,123.49/28.80
  6. Step 6: Final answer
    x = 39.01

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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.