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Finding the Fourth Proportional to 611.07, 842.86 and 390.30

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Solution

The fourth proportional to 611.07, 842.86 and 390.30 is: 538.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.07 : 842.86 = 390.30 : x
  2. Step 2: Convert to fraction form
    611.07/842.86 = 390.30/x
  3. Step 3: Cross multiply
    611.07x = 842.86 × 390.30
  4. Step 4: Simplify right side
    611.07x = 328,968.26
  5. Step 5: Solve for x
    x = 328,968.26/611.07
  6. Step 6: Final answer
    x = 538.35

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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.