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Finding the Fourth Proportional to 992.70, 1,370.28 and 638.88

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Solution

The fourth proportional to 992.70, 1,370.28 and 638.88 is: 881.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    992.70 : 1,370.28 = 638.88 : x
  2. Step 2: Convert to fraction form
    992.70/1,370.28 = 638.88/x
  3. Step 3: Cross multiply
    992.70x = 1,370.28 × 638.88
  4. Step 4: Simplify right side
    992.70x = 875,444.49
  5. Step 5: Solve for x
    x = 875,444.49/992.70
  6. Step 6: Final answer
    x = 881.88

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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.