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Finding the Fourth Proportional to 1,259.37, 1,890.78 and 643.49

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Solution

The fourth proportional to 1,259.37, 1,890.78 and 643.49 is: 966.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,259.37 : 1,890.78 = 643.49 : x
  2. Step 2: Convert to fraction form
    1,259.37/1,890.78 = 643.49/x
  3. Step 3: Cross multiply
    1,259.37x = 1,890.78 × 643.49
  4. Step 4: Simplify right side
    1,259.37x = 1,216,698.02
  5. Step 5: Solve for x
    x = 1,216,698.02/1,259.37
  6. Step 6: Final answer
    x = 966.12

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1.5x scale

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.