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Finding the Fourth Proportional to 287.76, 431.22 and 172.02

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Solution

The fourth proportional to 287.76, 431.22 and 172.02 is: 257.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.76 : 431.22 = 172.02 : x
  2. Step 2: Convert to fraction form
    287.76/431.22 = 172.02/x
  3. Step 3: Cross multiply
    287.76x = 431.22 × 172.02
  4. Step 4: Simplify right side
    287.76x = 74,178.46
  5. Step 5: Solve for x
    x = 74,178.46/287.76
  6. Step 6: Final answer
    x = 257.78

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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.