Home / 1,390.78-2,087.20-1,120.14

Finding the Fourth Proportional to 1,390.78, 2,087.20 and 1,120.14

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Solution

The fourth proportional to 1,390.78, 2,087.20 and 1,120.14 is: 1,681.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.78 : 2,087.20 = 1,120.14 : x
  2. Step 2: Convert to fraction form
    1,390.78/2,087.20 = 1,120.14/x
  3. Step 3: Cross multiply
    1,390.78x = 2,087.20 × 1,120.14
  4. Step 4: Simplify right side
    1,390.78x = 2,337,956.21
  5. Step 5: Solve for x
    x = 2,337,956.21/1,390.78
  6. Step 6: Final answer
    x = 1,681.04

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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.