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Finding the Fourth Proportional to 715.80, 1,072.80 and 391.44

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Solution

The fourth proportional to 715.80, 1,072.80 and 391.44 is: 586.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.80 : 1,072.80 = 391.44 : x
  2. Step 2: Convert to fraction form
    715.80/1,072.80 = 391.44/x
  3. Step 3: Cross multiply
    715.80x = 1,072.80 × 391.44
  4. Step 4: Simplify right side
    715.80x = 419,936.83
  5. Step 5: Solve for x
    x = 419,936.83/715.80
  6. Step 6: Final answer
    x = 586.67

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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.