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Finding the Fourth Proportional to 1,317.71, 1,818.36 and 728.21

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Solution

The fourth proportional to 1,317.71, 1,818.36 and 728.21 is: 1,004.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,317.71 : 1,818.36 = 728.21 : x
  2. Step 2: Convert to fraction form
    1,317.71/1,818.36 = 728.21/x
  3. Step 3: Cross multiply
    1,317.71x = 1,818.36 × 728.21
  4. Step 4: Simplify right side
    1,317.71x = 1,324,138.84
  5. Step 5: Solve for x
    x = 1,324,138.84/1,317.71
  6. Step 6: Final answer
    x = 1,004.88

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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.