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Finding the Fourth Proportional to 666.51, 919.98 and 386.81

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Solution

The fourth proportional to 666.51, 919.98 and 386.81 is: 533.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.51 : 919.98 = 386.81 : x
  2. Step 2: Convert to fraction form
    666.51/919.98 = 386.81/x
  3. Step 3: Cross multiply
    666.51x = 919.98 × 386.81
  4. Step 4: Simplify right side
    666.51x = 355,857.46
  5. Step 5: Solve for x
    x = 355,857.46/666.51
  6. Step 6: Final answer
    x = 533.91

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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.