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Finding the Fourth Proportional to 287.79, 431.70 and 82.39

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Solution

The fourth proportional to 287.79, 431.70 and 82.39 is: 123.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.79 : 431.70 = 82.39 : x
  2. Step 2: Convert to fraction form
    287.79/431.70 = 82.39/x
  3. Step 3: Cross multiply
    287.79x = 431.70 × 82.39
  4. Step 4: Simplify right side
    287.79x = 35,565.84
  5. Step 5: Solve for x
    x = 35,565.84/287.79
  6. Step 6: Final answer
    x = 123.58

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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.