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Finding the Fourth Proportional to 611.16, 843.12 and 390

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Solution

The fourth proportional to 611.16, 843.12 and 390 is: 538.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.16 : 843.12 = 390 : x
  2. Step 2: Convert to fraction form
    611.16/843.12 = 390/x
  3. Step 3: Cross multiply
    611.16x = 843.12 × 390
  4. Step 4: Simplify right side
    611.16x = 328,816.80
  5. Step 5: Solve for x
    x = 328,816.80/611.16
  6. Step 6: Final answer
    x = 538.02

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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.