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Finding the Fourth Proportional to 690.90, 1,036.16 and 203.90

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Solution

The fourth proportional to 690.90, 1,036.16 and 203.90 is: 305.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.90 : 1,036.16 = 203.90 : x
  2. Step 2: Convert to fraction form
    690.90/1,036.16 = 203.90/x
  3. Step 3: Cross multiply
    690.90x = 1,036.16 × 203.90
  4. Step 4: Simplify right side
    690.90x = 211,273.02
  5. Step 5: Solve for x
    x = 211,273.02/690.90
  6. Step 6: Final answer
    x = 305.79

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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.