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Finding the Fourth Proportional to 287.69, 431.53 and 281.78

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Solution

The fourth proportional to 287.69, 431.53 and 281.78 is: 422.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.69 : 431.53 = 281.78 : x
  2. Step 2: Convert to fraction form
    287.69/431.53 = 281.78/x
  3. Step 3: Cross multiply
    287.69x = 431.53 × 281.78
  4. Step 4: Simplify right side
    287.69x = 121,595.28
  5. Step 5: Solve for x
    x = 121,595.28/287.69
  6. Step 6: Final answer
    x = 422.67

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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.