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Finding the Fourth Proportional to 782.21, 1,079.87 and 498.91

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Solution

The fourth proportional to 782.21, 1,079.87 and 498.91 is: 688.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.21 : 1,079.87 = 498.91 : x
  2. Step 2: Convert to fraction form
    782.21/1,079.87 = 498.91/x
  3. Step 3: Cross multiply
    782.21x = 1,079.87 × 498.91
  4. Step 4: Simplify right side
    782.21x = 538,754.77
  5. Step 5: Solve for x
    x = 538,754.77/782.21
  6. Step 6: Final answer
    x = 688.76

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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.