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Finding the Fourth Proportional to 826.21, 1,139.70 and 728.20

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Solution

The fourth proportional to 826.21, 1,139.70 and 728.20 is: 1,004.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    826.21 : 1,139.70 = 728.20 : x
  2. Step 2: Convert to fraction form
    826.21/1,139.70 = 728.20/x
  3. Step 3: Cross multiply
    826.21x = 1,139.70 × 728.20
  4. Step 4: Simplify right side
    826.21x = 829,929.54
  5. Step 5: Solve for x
    x = 829,929.54/826.21
  6. Step 6: Final answer
    x = 1,004.50

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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.