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Finding the Fourth Proportional to 687.07, 947.91 and 421.48

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Solution

The fourth proportional to 687.07, 947.91 and 421.48 is: 581.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.07 : 947.91 = 421.48 : x
  2. Step 2: Convert to fraction form
    687.07/947.91 = 421.48/x
  3. Step 3: Cross multiply
    687.07x = 947.91 × 421.48
  4. Step 4: Simplify right side
    687.07x = 399,525.11
  5. Step 5: Solve for x
    x = 399,525.11/687.07
  6. Step 6: Final answer
    x = 581.49

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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.