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Finding the Fourth Proportional to 666.25, 919.43 and 390.25

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Solution

The fourth proportional to 666.25, 919.43 and 390.25 is: 538.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.25 : 919.43 = 390.25 : x
  2. Step 2: Convert to fraction form
    666.25/919.43 = 390.25/x
  3. Step 3: Cross multiply
    666.25x = 919.43 × 390.25
  4. Step 4: Simplify right side
    666.25x = 358,807.56
  5. Step 5: Solve for x
    x = 358,807.56/666.25
  6. Step 6: Final answer
    x = 538.55

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1.5x scale

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.