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Finding the Fourth Proportional to 687.81, 948.90 and 478.16

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Solution

The fourth proportional to 687.81, 948.90 and 478.16 is: 659.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.81 : 948.90 = 478.16 : x
  2. Step 2: Convert to fraction form
    687.81/948.90 = 478.16/x
  3. Step 3: Cross multiply
    687.81x = 948.90 × 478.16
  4. Step 4: Simplify right side
    687.81x = 453,719.49
  5. Step 5: Solve for x
    x = 453,719.49/687.81
  6. Step 6: Final answer
    x = 659.66

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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.