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Finding the Fourth Proportional to 287.51, 431.28 and 71.09

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Solution

The fourth proportional to 287.51, 431.28 and 71.09 is: 106.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.51 : 431.28 = 71.09 : x
  2. Step 2: Convert to fraction form
    287.51/431.28 = 71.09/x
  3. Step 3: Cross multiply
    287.51x = 431.28 × 71.09
  4. Step 4: Simplify right side
    287.51x = 30,659.70
  5. Step 5: Solve for x
    x = 30,659.70/287.51
  6. Step 6: Final answer
    x = 106.64

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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.