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Finding the Fourth Proportional to 687.03, 947.70 and 640.59

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Solution

The fourth proportional to 687.03, 947.70 and 640.59 is: 883.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.03 : 947.70 = 640.59 : x
  2. Step 2: Convert to fraction form
    687.03/947.70 = 640.59/x
  3. Step 3: Cross multiply
    687.03x = 947.70 × 640.59
  4. Step 4: Simplify right side
    687.03x = 607,087.14
  5. Step 5: Solve for x
    x = 607,087.14/687.03
  6. Step 6: Final answer
    x = 883.64

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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.