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Finding the Fourth Proportional to 687.40, 948.52 and 421.80

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Solution

The fourth proportional to 687.40, 948.52 and 421.80 is: 582.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.40 : 948.52 = 421.80 : x
  2. Step 2: Convert to fraction form
    687.40/948.52 = 421.80/x
  3. Step 3: Cross multiply
    687.40x = 948.52 × 421.80
  4. Step 4: Simplify right side
    687.40x = 400,085.74
  5. Step 5: Solve for x
    x = 400,085.74/687.40
  6. Step 6: Final answer
    x = 582.03

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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.