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Finding the Fourth Proportional to 690.28, 1,035.72 and 280.22

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Solution

The fourth proportional to 690.28, 1,035.72 and 280.22 is: 420.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.28 : 1,035.72 = 280.22 : x
  2. Step 2: Convert to fraction form
    690.28/1,035.72 = 280.22/x
  3. Step 3: Cross multiply
    690.28x = 1,035.72 × 280.22
  4. Step 4: Simplify right side
    690.28x = 290,229.46
  5. Step 5: Solve for x
    x = 290,229.46/690.28
  6. Step 6: Final answer
    x = 420.45

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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.