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Finding the Fourth Proportional to 1,387.31, 2,080.25 and 770.09

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Solution

The fourth proportional to 1,387.31, 2,080.25 and 770.09 is: 1,154.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.31 : 2,080.25 = 770.09 : x
  2. Step 2: Convert to fraction form
    1,387.31/2,080.25 = 770.09/x
  3. Step 3: Cross multiply
    1,387.31x = 2,080.25 × 770.09
  4. Step 4: Simplify right side
    1,387.31x = 1,601,975.87
  5. Step 5: Solve for x
    x = 1,601,975.87/1,387.31
  6. Step 6: Final answer
    x = 1,154.74

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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.