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Finding the Fourth Proportional to 1,213.49, 1,820.21 and 391.74

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Solution

The fourth proportional to 1,213.49, 1,820.21 and 391.74 is: 587.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,213.49 : 1,820.21 = 391.74 : x
  2. Step 2: Convert to fraction form
    1,213.49/1,820.21 = 391.74/x
  3. Step 3: Cross multiply
    1,213.49x = 1,820.21 × 391.74
  4. Step 4: Simplify right side
    1,213.49x = 713,047.11
  5. Step 5: Solve for x
    x = 713,047.11/1,213.49
  6. Step 6: Final answer
    x = 587.60

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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.