Home / 1,281.20-1,921.80-511.70

Finding the Fourth Proportional to 1,281.20, 1,921.80 and 511.70

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Solution

The fourth proportional to 1,281.20, 1,921.80 and 511.70 is: 767.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.20 : 1,921.80 = 511.70 : x
  2. Step 2: Convert to fraction form
    1,281.20/1,921.80 = 511.70/x
  3. Step 3: Cross multiply
    1,281.20x = 1,921.80 × 511.70
  4. Step 4: Simplify right side
    1,281.20x = 983,375.45
  5. Step 5: Solve for x
    x = 983,375.45/1,281.20
  6. Step 6: Final answer
    x = 767.55

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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.