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Finding the Fourth Proportional to 521.67, 719.96 and 390.45

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Solution

The fourth proportional to 521.67, 719.96 and 390.45 is: 538.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.67 : 719.96 = 390.45 : x
  2. Step 2: Convert to fraction form
    521.67/719.96 = 390.45/x
  3. Step 3: Cross multiply
    521.67x = 719.96 × 390.45
  4. Step 4: Simplify right side
    521.67x = 281,108.38
  5. Step 5: Solve for x
    x = 281,108.38/521.67
  6. Step 6: Final answer
    x = 538.86

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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.