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Finding the Fourth Proportional to 809.48, 1,119.33 and 643.40

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Solution

The fourth proportional to 809.48, 1,119.33 and 643.40 is: 889.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.48 : 1,119.33 = 643.40 : x
  2. Step 2: Convert to fraction form
    809.48/1,119.33 = 643.40/x
  3. Step 3: Cross multiply
    809.48x = 1,119.33 × 643.40
  4. Step 4: Simplify right side
    809.48x = 720,176.92
  5. Step 5: Solve for x
    x = 720,176.92/809.48
  6. Step 6: Final answer
    x = 889.68

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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.