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Finding the Fourth Proportional to 259.45, 388.90 and 115

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Solution

The fourth proportional to 259.45, 388.90 and 115 is: 172.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    259.45 : 388.90 = 115 : x
  2. Step 2: Convert to fraction form
    259.45/388.90 = 115/x
  3. Step 3: Cross multiply
    259.45x = 388.90 × 115
  4. Step 4: Simplify right side
    259.45x = 44,723.50
  5. Step 5: Solve for x
    x = 44,723.50/259.45
  6. Step 6: Final answer
    x = 172.38

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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.