Home / 1,286.21-1,921.49-820.28

Finding the Fourth Proportional to 1,286.21, 1,921.49 and 820.28

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Solution

The fourth proportional to 1,286.21, 1,921.49 and 820.28 is: 1,225.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.21 : 1,921.49 = 820.28 : x
  2. Step 2: Convert to fraction form
    1,286.21/1,921.49 = 820.28/x
  3. Step 3: Cross multiply
    1,286.21x = 1,921.49 × 820.28
  4. Step 4: Simplify right side
    1,286.21x = 1,576,146.11
  5. Step 5: Solve for x
    x = 1,576,146.11/1,286.21
  6. Step 6: Final answer
    x = 1,225.42

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.