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Finding the Fourth Proportional to 12,312.80, 18,488.40 and 7,128.80

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Solution

The fourth proportional to 12,312.80, 18,488.40 and 7,128.80 is: 10,704.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    12,312.80 : 18,488.40 = 7,128.80 : x
  2. Step 2: Convert to fraction form
    12,312.80/18,488.40 = 7,128.80/x
  3. Step 3: Cross multiply
    12,312.80x = 18,488.40 × 7,128.80
  4. Step 4: Simplify right side
    12,312.80x = 131,800,105.92
  5. Step 5: Solve for x
    x = 131,800,105.92/12,312.80
  6. Step 6: Final answer
    x = 10,704.32

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1.5x scale

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.