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Finding the Fourth Proportional to 287.15, 430.59 and 81.67

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Solution

The fourth proportional to 287.15, 430.59 and 81.67 is: 122.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.15 : 430.59 = 81.67 : x
  2. Step 2: Convert to fraction form
    287.15/430.59 = 81.67/x
  3. Step 3: Cross multiply
    287.15x = 430.59 × 81.67
  4. Step 4: Simplify right side
    287.15x = 35,165.96
  5. Step 5: Solve for x
    x = 35,165.96/287.15
  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.