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Finding the Fourth Proportional to 1,386.09, 1,912.73 and 765.09

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Solution

The fourth proportional to 1,386.09, 1,912.73 and 765.09 is: 1,055.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,386.09 : 1,912.73 = 765.09 : x
  2. Step 2: Convert to fraction form
    1,386.09/1,912.73 = 765.09/x
  3. Step 3: Cross multiply
    1,386.09x = 1,912.73 × 765.09
  4. Step 4: Simplify right side
    1,386.09x = 1,463,406.77
  5. Step 5: Solve for x
    x = 1,463,406.77/1,386.09
  6. Step 6: Final answer
    x = 1,055.78

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.