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Finding the Fourth Proportional to 287.53, 431.28 and 143.20

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Solution

The fourth proportional to 287.53, 431.28 and 143.20 is: 214.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.53 : 431.28 = 143.20 : x
  2. Step 2: Convert to fraction form
    287.53/431.28 = 143.20/x
  3. Step 3: Cross multiply
    287.53x = 431.28 × 143.20
  4. Step 4: Simplify right side
    287.53x = 61,759.30
  5. Step 5: Solve for x
    x = 61,759.30/287.53
  6. Step 6: Final answer
    x = 214.79

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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.