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Finding the Fourth Proportional to 687.18, 947.90 and 425

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Solution

The fourth proportional to 687.18, 947.90 and 425 is: 586.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.18 : 947.90 = 425 : x
  2. Step 2: Convert to fraction form
    687.18/947.90 = 425/x
  3. Step 3: Cross multiply
    687.18x = 947.90 × 425
  4. Step 4: Simplify right side
    687.18x = 402,857.50
  5. Step 5: Solve for x
    x = 402,857.50/687.18
  6. Step 6: Final answer
    x = 586.25

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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.