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Finding the Fourth Proportional to 811.47, 1,119.45 and 479.78

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Solution

The fourth proportional to 811.47, 1,119.45 and 479.78 is: 661.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.47 : 1,119.45 = 479.78 : x
  2. Step 2: Convert to fraction form
    811.47/1,119.45 = 479.78/x
  3. Step 3: Cross multiply
    811.47x = 1,119.45 × 479.78
  4. Step 4: Simplify right side
    811.47x = 537,089.72
  5. Step 5: Solve for x
    x = 537,089.72/811.47
  6. Step 6: Final answer
    x = 661.87

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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.