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Finding the Fourth Proportional to 987.26, 1,362.90 and 638.15

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Solution

The fourth proportional to 987.26, 1,362.90 and 638.15 is: 880.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.26 : 1,362.90 = 638.15 : x
  2. Step 2: Convert to fraction form
    987.26/1,362.90 = 638.15/x
  3. Step 3: Cross multiply
    987.26x = 1,362.90 × 638.15
  4. Step 4: Simplify right side
    987.26x = 869,734.64
  5. Step 5: Solve for x
    x = 869,734.64/987.26
  6. Step 6: Final answer
    x = 880.96

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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.