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Finding the Fourth Proportional to 690.18, 1,035.24 and 279.20

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Solution

The fourth proportional to 690.18, 1,035.24 and 279.20 is: 418.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.18 : 1,035.24 = 279.20 : x
  2. Step 2: Convert to fraction form
    690.18/1,035.24 = 279.20/x
  3. Step 3: Cross multiply
    690.18x = 1,035.24 × 279.20
  4. Step 4: Simplify right side
    690.18x = 289,039.01
  5. Step 5: Solve for x
    x = 289,039.01/690.18
  6. Step 6: Final answer
    x = 418.79

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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.