Home / 1,221.20-1,685.51-828.35

Finding the Fourth Proportional to 1,221.20, 1,685.51 and 828.35

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Solution

The fourth proportional to 1,221.20, 1,685.51 and 828.35 is: 1,143.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.20 : 1,685.51 = 828.35 : x
  2. Step 2: Convert to fraction form
    1,221.20/1,685.51 = 828.35/x
  3. Step 3: Cross multiply
    1,221.20x = 1,685.51 × 828.35
  4. Step 4: Simplify right side
    1,221.20x = 1,396,179.64
  5. Step 5: Solve for x
    x = 1,396,179.64/1,221.20
  6. Step 6: Final answer
    x = 1,143.29

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.