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Finding the Fourth Proportional to 611.37, 842.81 and 390.15

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Solution

The fourth proportional to 611.37, 842.81 and 390.15 is: 537.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.37 : 842.81 = 390.15 : x
  2. Step 2: Convert to fraction form
    611.37/842.81 = 390.15/x
  3. Step 3: Cross multiply
    611.37x = 842.81 × 390.15
  4. Step 4: Simplify right side
    611.37x = 328,820.37
  5. Step 5: Solve for x
    x = 328,820.37/611.37
  6. Step 6: Final answer
    x = 537.84

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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.