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Finding the Fourth Proportional to 992.42, 1,369.98 and 643.28

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Solution

The fourth proportional to 992.42, 1,369.98 and 643.28 is: 888.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    992.42 : 1,369.98 = 643.28 : x
  2. Step 2: Convert to fraction form
    992.42/1,369.98 = 643.28/x
  3. Step 3: Cross multiply
    992.42x = 1,369.98 × 643.28
  4. Step 4: Simplify right side
    992.42x = 881,280.73
  5. Step 5: Solve for x
    x = 881,280.73/992.42
  6. Step 6: Final answer
    x = 888.01

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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.