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Finding the Fourth Proportional to 3,430, 5,145 and 1,121.50

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Solution

The fourth proportional to 3,430, 5,145 and 1,121.50 is: 1,682.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,430 : 5,145 = 1,121.50 : x
  2. Step 2: Convert to fraction form
    3,430/5,145 = 1,121.50/x
  3. Step 3: Cross multiply
    3,430x = 5,145 × 1,121.50
  4. Step 4: Simplify right side
    3,430x = 5,770,117.50
  5. Step 5: Solve for x
    x = 5,770,117.50/3,430
  6. Step 6: Final answer
    x = 1,682.25

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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.