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Finding the Fourth Proportional to 1,288.53, 1,933.74 and 639.45

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Solution

The fourth proportional to 1,288.53, 1,933.74 and 639.45 is: 959.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.53 : 1,933.74 = 639.45 : x
  2. Step 2: Convert to fraction form
    1,288.53/1,933.74 = 639.45/x
  3. Step 3: Cross multiply
    1,288.53x = 1,933.74 × 639.45
  4. Step 4: Simplify right side
    1,288.53x = 1,236,530.04
  5. Step 5: Solve for x
    x = 1,236,530.04/1,288.53
  6. Step 6: Final answer
    x = 959.64

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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.