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Finding the Fourth Proportional to 780.21, 1,170.78 and 317.93

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Solution

The fourth proportional to 780.21, 1,170.78 and 317.93 is: 477.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.21 : 1,170.78 = 317.93 : x
  2. Step 2: Convert to fraction form
    780.21/1,170.78 = 317.93/x
  3. Step 3: Cross multiply
    780.21x = 1,170.78 × 317.93
  4. Step 4: Simplify right side
    780.21x = 372,219.04
  5. Step 5: Solve for x
    x = 372,219.04/780.21
  6. Step 6: Final answer
    x = 477.08

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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.