Home / 1,390.28-1,912.58-1,257.80

Finding the Fourth Proportional to 1,390.28, 1,912.58 and 1,257.80

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Solution

The fourth proportional to 1,390.28, 1,912.58 and 1,257.80 is: 1,730.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.28 : 1,912.58 = 1,257.80 : x
  2. Step 2: Convert to fraction form
    1,390.28/1,912.58 = 1,257.80/x
  3. Step 3: Cross multiply
    1,390.28x = 1,912.58 × 1,257.80
  4. Step 4: Simplify right side
    1,390.28x = 2,405,643.12
  5. Step 5: Solve for x
    x = 2,405,643.12/1,390.28
  6. Step 6: Final answer
    x = 1,730.33

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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.