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Finding the Fourth Proportional to 1,215.90, 1,820.61 and 728.28

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Solution

The fourth proportional to 1,215.90, 1,820.61 and 728.28 is: 1,090.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,215.90 : 1,820.61 = 728.28 : x
  2. Step 2: Convert to fraction form
    1,215.90/1,820.61 = 728.28/x
  3. Step 3: Cross multiply
    1,215.90x = 1,820.61 × 728.28
  4. Step 4: Simplify right side
    1,215.90x = 1,325,913.85
  5. Step 5: Solve for x
    x = 1,325,913.85/1,215.90
  6. Step 6: Final answer
    x = 1,090.48

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.