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Finding the Fourth Proportional to 621.16, 858.30 and 491.20

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Solution

The fourth proportional to 621.16, 858.30 and 491.20 is: 678.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.16 : 858.30 = 491.20 : x
  2. Step 2: Convert to fraction form
    621.16/858.30 = 491.20/x
  3. Step 3: Cross multiply
    621.16x = 858.30 × 491.20
  4. Step 4: Simplify right side
    621.16x = 421,596.96
  5. Step 5: Solve for x
    x = 421,596.96/621.16
  6. Step 6: Final answer
    x = 678.73

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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.