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Finding the Fourth Proportional to 687.21, 1,031.88 and 414.51

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Solution

The fourth proportional to 687.21, 1,031.88 and 414.51 is: 622.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.21 : 1,031.88 = 414.51 : x
  2. Step 2: Convert to fraction form
    687.21/1,031.88 = 414.51/x
  3. Step 3: Cross multiply
    687.21x = 1,031.88 × 414.51
  4. Step 4: Simplify right side
    687.21x = 427,724.58
  5. Step 5: Solve for x
    x = 427,724.58/687.21
  6. Step 6: Final answer
    x = 622.41

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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.