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Finding the Fourth Proportional to 491.31, 678.84 and 386.63

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Solution

The fourth proportional to 491.31, 678.84 and 386.63 is: 534.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.31 : 678.84 = 386.63 : x
  2. Step 2: Convert to fraction form
    491.31/678.84 = 386.63/x
  3. Step 3: Cross multiply
    491.31x = 678.84 × 386.63
  4. Step 4: Simplify right side
    491.31x = 262,456.52
  5. Step 5: Solve for x
    x = 262,456.52/491.31
  6. Step 6: Final answer
    x = 534.20

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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.