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Finding the Fourth Proportional to 998.65, 1,378.30 and 719.81

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Solution

The fourth proportional to 998.65, 1,378.30 and 719.81 is: 993.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    998.65 : 1,378.30 = 719.81 : x
  2. Step 2: Convert to fraction form
    998.65/1,378.30 = 719.81/x
  3. Step 3: Cross multiply
    998.65x = 1,378.30 × 719.81
  4. Step 4: Simplify right side
    998.65x = 992,105.43
  5. Step 5: Solve for x
    x = 992,105.43/998.65
  6. Step 6: Final answer
    x = 993.45

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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.