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Finding the Fourth Proportional to 259.21, 388.66 and 128.92

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Solution

The fourth proportional to 259.21, 388.66 and 128.92 is: 193.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.21 : 388.66 = 128.92 : x
  2. Step 2: Convert to fraction form
    259.21/388.66 = 128.92/x
  3. Step 3: Cross multiply
    259.21x = 388.66 × 128.92
  4. Step 4: Simplify right side
    259.21x = 50,106.05
  5. Step 5: Solve for x
    x = 50,106.05/259.21
  6. Step 6: Final answer
    x = 193.30

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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.