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Finding the Fourth Proportional to 7,120.80, 9,815.04 and 5,128.56

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Solution

The fourth proportional to 7,120.80, 9,815.04 and 5,128.56 is: 7,069.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    7,120.80 : 9,815.04 = 5,128.56 : x
  2. Step 2: Convert to fraction form
    7,120.80/9,815.04 = 5,128.56/x
  3. Step 3: Cross multiply
    7,120.80x = 9,815.04 × 5,128.56
  4. Step 4: Simplify right side
    7,120.80x = 50,337,021.54
  5. Step 5: Solve for x
    x = 50,337,021.54/7,120.80
  6. Step 6: Final answer
    x = 7,069.01

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1.5x scale

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.