Home / 1,121.28-1,681.08-390.48

Finding the Fourth Proportional to 1,121.28, 1,681.08 and 390.48

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Solution

The fourth proportional to 1,121.28, 1,681.08 and 390.48 is: 585.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,121.28 : 1,681.08 = 390.48 : x
  2. Step 2: Convert to fraction form
    1,121.28/1,681.08 = 390.48/x
  3. Step 3: Cross multiply
    1,121.28x = 1,681.08 × 390.48
  4. Step 4: Simplify right side
    1,121.28x = 656,428.12
  5. Step 5: Solve for x
    x = 656,428.12/1,121.28
  6. Step 6: Final answer
    x = 585.43

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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.