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Finding the Fourth Proportional to 712.08, 982.80 and 491.31

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Solution

The fourth proportional to 712.08, 982.80 and 491.31 is: 678.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.08 : 982.80 = 491.31 : x
  2. Step 2: Convert to fraction form
    712.08/982.80 = 491.31/x
  3. Step 3: Cross multiply
    712.08x = 982.80 × 491.31
  4. Step 4: Simplify right side
    712.08x = 482,859.47
  5. Step 5: Solve for x
    x = 482,859.47/712.08
  6. Step 6: Final answer
    x = 678.10

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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.