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Finding the Fourth Proportional to 690.76, 1,036.32 and 280.12

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Solution

The fourth proportional to 690.76, 1,036.32 and 280.12 is: 420.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.76 : 1,036.32 = 280.12 : x
  2. Step 2: Convert to fraction form
    690.76/1,036.32 = 280.12/x
  3. Step 3: Cross multiply
    690.76x = 1,036.32 × 280.12
  4. Step 4: Simplify right side
    690.76x = 290,293.96
  5. Step 5: Solve for x
    x = 290,293.96/690.76
  6. Step 6: Final answer
    x = 420.25

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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.