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Finding the Fourth Proportional to 992.10, 1,369.24 and 643.38

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Solution

The fourth proportional to 992.10, 1,369.24 and 643.38 is: 887.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    992.10 : 1,369.24 = 643.38 : x
  2. Step 2: Convert to fraction form
    992.10/1,369.24 = 643.38/x
  3. Step 3: Cross multiply
    992.10x = 1,369.24 × 643.38
  4. Step 4: Simplify right side
    992.10x = 880,941.63
  5. Step 5: Solve for x
    x = 880,941.63/992.10
  6. Step 6: Final answer
    x = 887.96

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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.