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Finding the Fourth Proportional to 642.99, 887.31 and 381

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Solution

The fourth proportional to 642.99, 887.31 and 381 is: 525.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.99 : 887.31 = 381 : x
  2. Step 2: Convert to fraction form
    642.99/887.31 = 381/x
  3. Step 3: Cross multiply
    642.99x = 887.31 × 381
  4. Step 4: Simplify right side
    642.99x = 338,065.11
  5. Step 5: Solve for x
    x = 338,065.11/642.99
  6. Step 6: Final answer
    x = 525.77

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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.