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Finding the Fourth Proportional to 687.93, 948.40 and 666.39

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Solution

The fourth proportional to 687.93, 948.40 and 666.39 is: 918.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.93 : 948.40 = 666.39 : x
  2. Step 2: Convert to fraction form
    687.93/948.40 = 666.39/x
  3. Step 3: Cross multiply
    687.93x = 948.40 × 666.39
  4. Step 4: Simplify right side
    687.93x = 632,004.28
  5. Step 5: Solve for x
    x = 632,004.28/687.93
  6. Step 6: Final answer
    x = 918.70

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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.