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Finding the Fourth Proportional to 621.71, 931.93 and 390.76

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Solution

The fourth proportional to 621.71, 931.93 and 390.76 is: 585.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.71 : 931.93 = 390.76 : x
  2. Step 2: Convert to fraction form
    621.71/931.93 = 390.76/x
  3. Step 3: Cross multiply
    621.71x = 931.93 × 390.76
  4. Step 4: Simplify right side
    621.71x = 364,157.66
  5. Step 5: Solve for x
    x = 364,157.66/621.71
  6. Step 6: Final answer
    x = 585.74

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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.