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Finding the Fourth Proportional to 1,278.71, 1,918.05 and 413

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Solution

The fourth proportional to 1,278.71, 1,918.05 and 413 is: 619.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.71 : 1,918.05 = 413 : x
  2. Step 2: Convert to fraction form
    1,278.71/1,918.05 = 413/x
  3. Step 3: Cross multiply
    1,278.71x = 1,918.05 × 413
  4. Step 4: Simplify right side
    1,278.71x = 792,154.65
  5. Step 5: Solve for x
    x = 792,154.65/1,278.71
  6. Step 6: Final answer
    x = 619.50

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Half scale
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Double scale
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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.