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Finding the Fourth Proportional to 1,389.97, 1,918.38 and 859.15

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Solution

The fourth proportional to 1,389.97, 1,918.38 and 859.15 is: 1,185.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.97 : 1,918.38 = 859.15 : x
  2. Step 2: Convert to fraction form
    1,389.97/1,918.38 = 859.15/x
  3. Step 3: Cross multiply
    1,389.97x = 1,918.38 × 859.15
  4. Step 4: Simplify right side
    1,389.97x = 1,648,176.18
  5. Step 5: Solve for x
    x = 1,648,176.18/1,389.97
  6. Step 6: Final answer
    x = 1,185.76

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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.