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Finding the Fourth Proportional to 1,387.81, 2,080.99 and 770.59

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Solution

The fourth proportional to 1,387.81, 2,080.99 and 770.59 is: 1,155.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.81 : 2,080.99 = 770.59 : x
  2. Step 2: Convert to fraction form
    1,387.81/2,080.99 = 770.59/x
  3. Step 3: Cross multiply
    1,387.81x = 2,080.99 × 770.59
  4. Step 4: Simplify right side
    1,387.81x = 1,603,590.08
  5. Step 5: Solve for x
    x = 1,603,590.08/1,387.81
  6. Step 6: Final answer
    x = 1,155.48

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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.