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Finding the Fourth Proportional to 986.81, 1,480.21 and 678.58

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Solution

The fourth proportional to 986.81, 1,480.21 and 678.58 is: 1,017.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    986.81 : 1,480.21 = 678.58 : x
  2. Step 2: Convert to fraction form
    986.81/1,480.21 = 678.58/x
  3. Step 3: Cross multiply
    986.81x = 1,480.21 × 678.58
  4. Step 4: Simplify right side
    986.81x = 1,004,438.37
  5. Step 5: Solve for x
    x = 1,004,438.37/986.81
  6. Step 6: Final answer
    x = 1,017.87

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.