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Finding the Fourth Proportional to 690.20, 1,035.42 and 305.72

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Solution

The fourth proportional to 690.20, 1,035.42 and 305.72 is: 458.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.20 : 1,035.42 = 305.72 : x
  2. Step 2: Convert to fraction form
    690.20/1,035.42 = 305.72/x
  3. Step 3: Cross multiply
    690.20x = 1,035.42 × 305.72
  4. Step 4: Simplify right side
    690.20x = 316,548.60
  5. Step 5: Solve for x
    x = 316,548.60/690.20
  6. Step 6: Final answer
    x = 458.63

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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.