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Finding the Fourth Proportional to 287.40, 431.31 and 165.74

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Solution

The fourth proportional to 287.40, 431.31 and 165.74 is: 248.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.40 : 431.31 = 165.74 : x
  2. Step 2: Convert to fraction form
    287.40/431.31 = 165.74/x
  3. Step 3: Cross multiply
    287.40x = 431.31 × 165.74
  4. Step 4: Simplify right side
    287.40x = 71,483.16
  5. Step 5: Solve for x
    x = 71,483.16/287.40
  6. Step 6: Final answer
    x = 248.72

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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.