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Finding the Fourth Proportional to 388.80, 583.20 and 172.40

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Solution

The fourth proportional to 388.80, 583.20 and 172.40 is: 258.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    388.80 : 583.20 = 172.40 : x
  2. Step 2: Convert to fraction form
    388.80/583.20 = 172.40/x
  3. Step 3: Cross multiply
    388.80x = 583.20 × 172.40
  4. Step 4: Simplify right side
    388.80x = 100,540.76
  5. Step 5: Solve for x
    x = 100,540.76/388.80
  6. Step 6: Final answer
    x = 258.59

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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.