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Finding the Fourth Proportional to 1,380.80, 2,071.21 and 688.33

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Solution

The fourth proportional to 1,380.80, 2,071.21 and 688.33 is: 1,032.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380.80 : 2,071.21 = 688.33 : x
  2. Step 2: Convert to fraction form
    1,380.80/2,071.21 = 688.33/x
  3. Step 3: Cross multiply
    1,380.80x = 2,071.21 × 688.33
  4. Step 4: Simplify right side
    1,380.80x = 1,425,669.08
  5. Step 5: Solve for x
    x = 1,425,669.08/1,380.80
  6. Step 6: Final answer
    x = 1,032.49

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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.