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Finding the Fourth Proportional to 690.75, 1,035.72 and 280.08

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Solution

The fourth proportional to 690.75, 1,035.72 and 280.08 is: 419.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.75 : 1,035.72 = 280.08 : x
  2. Step 2: Convert to fraction form
    690.75/1,035.72 = 280.08/x
  3. Step 3: Cross multiply
    690.75x = 1,035.72 × 280.08
  4. Step 4: Simplify right side
    690.75x = 290,084.46
  5. Step 5: Solve for x
    x = 290,084.46/690.75
  6. Step 6: Final answer
    x = 419.96

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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.