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Finding the Fourth Proportional to 500.74, 690.87 and 390.22

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Solution

The fourth proportional to 500.74, 690.87 and 390.22 is: 538.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    500.74 : 690.87 = 390.22 : x
  2. Step 2: Convert to fraction form
    500.74/690.87 = 390.22/x
  3. Step 3: Cross multiply
    500.74x = 690.87 × 390.22
  4. Step 4: Simplify right side
    500.74x = 269,591.03
  5. Step 5: Solve for x
    x = 269,591.03/500.74
  6. Step 6: Final answer
    x = 538.39

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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.