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Finding the Fourth Proportional to 784.40, 1,084.52 and 687.20

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Solution

The fourth proportional to 784.40, 1,084.52 and 687.20 is: 950.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.40 : 1,084.52 = 687.20 : x
  2. Step 2: Convert to fraction form
    784.40/1,084.52 = 687.20/x
  3. Step 3: Cross multiply
    784.40x = 1,084.52 × 687.20
  4. Step 4: Simplify right side
    784.40x = 745,282.14
  5. Step 5: Solve for x
    x = 745,282.14/784.40
  6. Step 6: Final answer
    x = 950.13

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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.