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Finding the Fourth Proportional to 687.21, 1,035.74 and 647.52

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Solution

The fourth proportional to 687.21, 1,035.74 and 647.52 is: 975.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.21 : 1,035.74 = 647.52 : x
  2. Step 2: Convert to fraction form
    687.21/1,035.74 = 647.52/x
  3. Step 3: Cross multiply
    687.21x = 1,035.74 × 647.52
  4. Step 4: Simplify right side
    687.21x = 670,662.36
  5. Step 5: Solve for x
    x = 670,662.36/687.21
  6. Step 6: Final answer
    x = 975.92

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.