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Finding the Fourth Proportional to 867.21, 1,300.78 and 319.15

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Solution

The fourth proportional to 867.21, 1,300.78 and 319.15 is: 478.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    867.21 : 1,300.78 = 319.15 : x
  2. Step 2: Convert to fraction form
    867.21/1,300.78 = 319.15/x
  3. Step 3: Cross multiply
    867.21x = 1,300.78 × 319.15
  4. Step 4: Simplify right side
    867.21x = 415,143.94
  5. Step 5: Solve for x
    x = 415,143.94/867.21
  6. Step 6: Final answer
    x = 478.71

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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.