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Finding the Fourth Proportional to 989.72, 1,364.24 and 779.57

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Solution

The fourth proportional to 989.72, 1,364.24 and 779.57 is: 1,074.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.72 : 1,364.24 = 779.57 : x
  2. Step 2: Convert to fraction form
    989.72/1,364.24 = 779.57/x
  3. Step 3: Cross multiply
    989.72x = 1,364.24 × 779.57
  4. Step 4: Simplify right side
    989.72x = 1,063,520.58
  5. Step 5: Solve for x
    x = 1,063,520.58/989.72
  6. Step 6: Final answer
    x = 1,074.57

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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.