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Finding the Fourth Proportional to 780.46, 1,170.36 and 390.36

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Solution

The fourth proportional to 780.46, 1,170.36 and 390.36 is: 585.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.46 : 1,170.36 = 390.36 : x
  2. Step 2: Convert to fraction form
    780.46/1,170.36 = 390.36/x
  3. Step 3: Cross multiply
    780.46x = 1,170.36 × 390.36
  4. Step 4: Simplify right side
    780.46x = 456,861.73
  5. Step 5: Solve for x
    x = 456,861.73/780.46
  6. Step 6: Final answer
    x = 585.37

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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.