Home / 1,311.20-1,809.45-721.73

Finding the Fourth Proportional to 1,311.20, 1,809.45 and 721.73

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Solution

The fourth proportional to 1,311.20, 1,809.45 and 721.73 is: 995.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,311.20 : 1,809.45 = 721.73 : x
  2. Step 2: Convert to fraction form
    1,311.20/1,809.45 = 721.73/x
  3. Step 3: Cross multiply
    1,311.20x = 1,809.45 × 721.73
  4. Step 4: Simplify right side
    1,311.20x = 1,305,925.30
  5. Step 5: Solve for x
    x = 1,305,925.30/1,311.20
  6. Step 6: Final answer
    x = 995.98

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1.5x scale

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.