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Finding the Fourth Proportional to 841.74, 1,261.40 and 409.20

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Solution

The fourth proportional to 841.74, 1,261.40 and 409.20 is: 613.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    841.74 : 1,261.40 = 409.20 : x
  2. Step 2: Convert to fraction form
    841.74/1,261.40 = 409.20/x
  3. Step 3: Cross multiply
    841.74x = 1,261.40 × 409.20
  4. Step 4: Simplify right side
    841.74x = 516,162.83
  5. Step 5: Solve for x
    x = 516,162.83/841.74
  6. Step 6: Final answer
    x = 613.21

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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.