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Finding the Fourth Proportional to 1,386.81, 2,080.11 and 412.91

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Solution

The fourth proportional to 1,386.81, 2,080.11 and 412.91 is: 619.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,386.81 : 2,080.11 = 412.91 : x
  2. Step 2: Convert to fraction form
    1,386.81/2,080.11 = 412.91/x
  3. Step 3: Cross multiply
    1,386.81x = 2,080.11 × 412.91
  4. Step 4: Simplify right side
    1,386.81x = 858,905.39
  5. Step 5: Solve for x
    x = 858,905.39/1,386.81
  6. Step 6: Final answer
    x = 619.34

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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.