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Finding the Fourth Proportional to 782.76, 1,079.34 and 642.44

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Solution

The fourth proportional to 782.76, 1,079.34 and 642.44 is: 885.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.76 : 1,079.34 = 642.44 : x
  2. Step 2: Convert to fraction form
    782.76/1,079.34 = 642.44/x
  3. Step 3: Cross multiply
    782.76x = 1,079.34 × 642.44
  4. Step 4: Simplify right side
    782.76x = 693,411.19
  5. Step 5: Solve for x
    x = 693,411.19/782.76
  6. Step 6: Final answer
    x = 885.85

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Double scale
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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.