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Finding the Fourth Proportional to 3,120.81, 4,681.17 and 780.80

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Solution

The fourth proportional to 3,120.81, 4,681.17 and 780.80 is: 1,171.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,120.81 : 4,681.17 = 780.80 : x
  2. Step 2: Convert to fraction form
    3,120.81/4,681.17 = 780.80/x
  3. Step 3: Cross multiply
    3,120.81x = 4,681.17 × 780.80
  4. Step 4: Simplify right side
    3,120.81x = 3,655,064.85
  5. Step 5: Solve for x
    x = 3,655,064.85/3,120.81
  6. Step 6: Final answer
    x = 1,171.19

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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.