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Finding the Fourth Proportional to 839.49, 1,259.13 and 428.92

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Solution

The fourth proportional to 839.49, 1,259.13 and 428.92 is: 643.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.49 : 1,259.13 = 428.92 : x
  2. Step 2: Convert to fraction form
    839.49/1,259.13 = 428.92/x
  3. Step 3: Cross multiply
    839.49x = 1,259.13 × 428.92
  4. Step 4: Simplify right side
    839.49x = 540,066.04
  5. Step 5: Solve for x
    x = 540,066.04/839.49
  6. Step 6: Final answer
    x = 643.33

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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.