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Finding the Fourth Proportional to 491.64, 678.42 and 381

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Solution

The fourth proportional to 491.64, 678.42 and 381 is: 525.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.64 : 678.42 = 381 : x
  2. Step 2: Convert to fraction form
    491.64/678.42 = 381/x
  3. Step 3: Cross multiply
    491.64x = 678.42 × 381
  4. Step 4: Simplify right side
    491.64x = 258,478.02
  5. Step 5: Solve for x
    x = 258,478.02/491.64
  6. Step 6: Final answer
    x = 525.75

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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.