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Finding the Fourth Proportional to 690.67, 1,036.52 and 431.05

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Solution

The fourth proportional to 690.67, 1,036.52 and 431.05 is: 646.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.67 : 1,036.52 = 431.05 : x
  2. Step 2: Convert to fraction form
    690.67/1,036.52 = 431.05/x
  3. Step 3: Cross multiply
    690.67x = 1,036.52 × 431.05
  4. Step 4: Simplify right side
    690.67x = 446,791.95
  5. Step 5: Solve for x
    x = 446,791.95/690.67
  6. Step 6: Final answer
    x = 646.90

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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.