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Finding the Fourth Proportional to 287.86, 431.86 and 131.70

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Solution

The fourth proportional to 287.86, 431.86 and 131.70 is: 197.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.86 : 431.86 = 131.70 : x
  2. Step 2: Convert to fraction form
    287.86/431.86 = 131.70/x
  3. Step 3: Cross multiply
    287.86x = 431.86 × 131.70
  4. Step 4: Simplify right side
    287.86x = 56,875.96
  5. Step 5: Solve for x
    x = 56,875.96/287.86
  6. Step 6: Final answer
    x = 197.58

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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.