Home / 1,109.20-1,661.40-987.60

Finding the Fourth Proportional to 1,109.20, 1,661.40 and 987.60

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Solution

The fourth proportional to 1,109.20, 1,661.40 and 987.60 is: 1,479.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,109.20 : 1,661.40 = 987.60 : x
  2. Step 2: Convert to fraction form
    1,109.20/1,661.40 = 987.60/x
  3. Step 3: Cross multiply
    1,109.20x = 1,661.40 × 987.60
  4. Step 4: Simplify right side
    1,109.20x = 1,640,798.64
  5. Step 5: Solve for x
    x = 1,640,798.64/1,109.20
  6. Step 6: Final answer
    x = 1,479.26

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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.