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Finding the Fourth Proportional to 992.47, 1,368.78 and 638.45

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Solution

The fourth proportional to 992.47, 1,368.78 and 638.45 is: 880.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    992.47 : 1,368.78 = 638.45 : x
  2. Step 2: Convert to fraction form
    992.47/1,368.78 = 638.45/x
  3. Step 3: Cross multiply
    992.47x = 1,368.78 × 638.45
  4. Step 4: Simplify right side
    992.47x = 873,897.59
  5. Step 5: Solve for x
    x = 873,897.59/992.47
  6. Step 6: Final answer
    x = 880.53

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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.