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Finding the Fourth Proportional to 287.76, 431.58 and 105.15

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Solution

The fourth proportional to 287.76, 431.58 and 105.15 is: 157.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.76 : 431.58 = 105.15 : x
  2. Step 2: Convert to fraction form
    287.76/431.58 = 105.15/x
  3. Step 3: Cross multiply
    287.76x = 431.58 × 105.15
  4. Step 4: Simplify right side
    287.76x = 45,382.65
  5. Step 5: Solve for x
    x = 45,382.65/287.76
  6. Step 6: Final answer
    x = 157.71

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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.