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Finding the Fourth Proportional to 687.21, 947.86 and 438.59

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Solution

The fourth proportional to 687.21, 947.86 and 438.59 is: 604.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.21 : 947.86 = 438.59 : x
  2. Step 2: Convert to fraction form
    687.21/947.86 = 438.59/x
  3. Step 3: Cross multiply
    687.21x = 947.86 × 438.59
  4. Step 4: Simplify right side
    687.21x = 415,721.92
  5. Step 5: Solve for x
    x = 415,721.92/687.21
  6. Step 6: Final answer
    x = 604.94

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.