Home / 1,121.08-1,681.80-390.64

Finding the Fourth Proportional to 1,121.08, 1,681.80 and 390.64

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Solution

The fourth proportional to 1,121.08, 1,681.80 and 390.64 is: 586.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,121.08 : 1,681.80 = 390.64 : x
  2. Step 2: Convert to fraction form
    1,121.08/1,681.80 = 390.64/x
  3. Step 3: Cross multiply
    1,121.08x = 1,681.80 × 390.64
  4. Step 4: Simplify right side
    1,121.08x = 656,978.35
  5. Step 5: Solve for x
    x = 656,978.35/1,121.08
  6. Step 6: Final answer
    x = 586.02

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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.