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Finding the Fourth Proportional to 998.87, 1,378.91 and 663.30

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Solution

The fourth proportional to 998.87, 1,378.91 and 663.30 is: 915.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    998.87 : 1,378.91 = 663.30 : x
  2. Step 2: Convert to fraction form
    998.87/1,378.91 = 663.30/x
  3. Step 3: Cross multiply
    998.87x = 1,378.91 × 663.30
  4. Step 4: Simplify right side
    998.87x = 914,632.66
  5. Step 5: Solve for x
    x = 914,632.66/998.87
  6. Step 6: Final answer
    x = 915.67

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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.