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Finding the Fourth Proportional to 999, 1,378.71 and 645.03

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Solution

The fourth proportional to 999, 1,378.71 and 645.03 is: 890.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    999 : 1,378.71 = 645.03 : x
  2. Step 2: Convert to fraction form
    999/1,378.71 = 645.03/x
  3. Step 3: Cross multiply
    999x = 1,378.71 × 645.03
  4. Step 4: Simplify right side
    999x = 889,309.31
  5. Step 5: Solve for x
    x = 889,309.31/999
  6. Step 6: Final answer
    x = 890.20

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.