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Finding the Fourth Proportional to 2,860.80, 4,291.20 and 780.80

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Solution

The fourth proportional to 2,860.80, 4,291.20 and 780.80 is: 1,171.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,860.80 : 4,291.20 = 780.80 : x
  2. Step 2: Convert to fraction form
    2,860.80/4,291.20 = 780.80/x
  3. Step 3: Cross multiply
    2,860.80x = 4,291.20 × 780.80
  4. Step 4: Simplify right side
    2,860.80x = 3,350,568.96
  5. Step 5: Solve for x
    x = 3,350,568.96/2,860.80
  6. Step 6: Final answer
    x = 1,171.20

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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.