Home / 1,389.60-2,082.78-811.26

Finding the Fourth Proportional to 1,389.60, 2,082.78 and 811.26

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Solution

The fourth proportional to 1,389.60, 2,082.78 and 811.26 is: 1,215.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.60 : 2,082.78 = 811.26 : x
  2. Step 2: Convert to fraction form
    1,389.60/2,082.78 = 811.26/x
  3. Step 3: Cross multiply
    1,389.60x = 2,082.78 × 811.26
  4. Step 4: Simplify right side
    1,389.60x = 1,689,676.10
  5. Step 5: Solve for x
    x = 1,689,676.10/1,389.60
  6. Step 6: Final answer
    x = 1,215.94

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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.