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Finding the Fourth Proportional to 287.07, 430.61 and 81.65

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Solution

The fourth proportional to 287.07, 430.61 and 81.65 is: 122.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.07 : 430.61 = 81.65 : x
  2. Step 2: Convert to fraction form
    287.07/430.61 = 81.65/x
  3. Step 3: Cross multiply
    287.07x = 430.61 × 81.65
  4. Step 4: Simplify right side
    287.07x = 35,156.75
  5. Step 5: Solve for x
    x = 35,156.75/287.07
  6. Step 6: Final answer
    x = 122.47

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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.