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Finding the Fourth Proportional to 2,812.80, 4,219.20 and 865.60

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Solution

The fourth proportional to 2,812.80, 4,219.20 and 865.60 is: 1,298.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,812.80 : 4,219.20 = 865.60 : x
  2. Step 2: Convert to fraction form
    2,812.80/4,219.20 = 865.60/x
  3. Step 3: Cross multiply
    2,812.80x = 4,219.20 × 865.60
  4. Step 4: Simplify right side
    2,812.80x = 3,652,139.52
  5. Step 5: Solve for x
    x = 3,652,139.52/2,812.80
  6. Step 6: Final answer
    x = 1,298.40

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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.