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Finding the Fourth Proportional to 689.85, 1,035.20 and 278.99

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Solution

The fourth proportional to 689.85, 1,035.20 and 278.99 is: 418.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.85 : 1,035.20 = 278.99 : x
  2. Step 2: Convert to fraction form
    689.85/1,035.20 = 278.99/x
  3. Step 3: Cross multiply
    689.85x = 1,035.20 × 278.99
  4. Step 4: Simplify right side
    689.85x = 288,810.45
  5. Step 5: Solve for x
    x = 288,810.45/689.85
  6. Step 6: Final answer
    x = 418.66

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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.