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Finding the Fourth Proportional to 1,278.75, 1,764.68 and 719.20

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Solution

The fourth proportional to 1,278.75, 1,764.68 and 719.20 is: 992.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.75 : 1,764.68 = 719.20 : x
  2. Step 2: Convert to fraction form
    1,278.75/1,764.68 = 719.20/x
  3. Step 3: Cross multiply
    1,278.75x = 1,764.68 × 719.20
  4. Step 4: Simplify right side
    1,278.75x = 1,269,157.86
  5. Step 5: Solve for x
    x = 1,269,157.86/1,278.75
  6. Step 6: Final answer
    x = 992.50

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Half scale
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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.