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Finding the Fourth Proportional to 867.64, 1,299.99 and 428.30

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Solution

The fourth proportional to 867.64, 1,299.99 and 428.30 is: 641.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    867.64 : 1,299.99 = 428.30 : x
  2. Step 2: Convert to fraction form
    867.64/1,299.99 = 428.30/x
  3. Step 3: Cross multiply
    867.64x = 1,299.99 × 428.30
  4. Step 4: Simplify right side
    867.64x = 556,785.72
  5. Step 5: Solve for x
    x = 556,785.72/867.64
  6. Step 6: Final answer
    x = 641.73

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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.