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Finding the Fourth Proportional to 208.80, 312.84 and 172.80

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Solution

The fourth proportional to 208.80, 312.84 and 172.80 is: 258.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.80 : 312.84 = 172.80 : x
  2. Step 2: Convert to fraction form
    208.80/312.84 = 172.80/x
  3. Step 3: Cross multiply
    208.80x = 312.84 × 172.80
  4. Step 4: Simplify right side
    208.80x = 54,058.75
  5. Step 5: Solve for x
    x = 54,058.75/208.80
  6. Step 6: Final answer
    x = 258.90

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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.