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Finding the Fourth Proportional to 1,287.88, 1,777.57 and 764.21

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Solution

The fourth proportional to 1,287.88, 1,777.57 and 764.21 is: 1,054.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.88 : 1,777.57 = 764.21 : x
  2. Step 2: Convert to fraction form
    1,287.88/1,777.57 = 764.21/x
  3. Step 3: Cross multiply
    1,287.88x = 1,777.57 × 764.21
  4. Step 4: Simplify right side
    1,287.88x = 1,358,436.77
  5. Step 5: Solve for x
    x = 1,358,436.77/1,287.88
  6. Step 6: Final answer
    x = 1,054.79

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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.