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Finding the Fourth Proportional to 992.28, 1,369.80 and 643.17

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Solution

The fourth proportional to 992.28, 1,369.80 and 643.17 is: 887.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    992.28 : 1,369.80 = 643.17 : x
  2. Step 2: Convert to fraction form
    992.28/1,369.80 = 643.17/x
  3. Step 3: Cross multiply
    992.28x = 1,369.80 × 643.17
  4. Step 4: Simplify right side
    992.28x = 881,014.27
  5. Step 5: Solve for x
    x = 881,014.27/992.28
  6. Step 6: Final answer
    x = 887.87

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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.