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Finding the Fourth Proportional to 780.36, 1,170.80 and 318.24

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Solution

The fourth proportional to 780.36, 1,170.80 and 318.24 is: 477.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.36 : 1,170.80 = 318.24 : x
  2. Step 2: Convert to fraction form
    780.36/1,170.80 = 318.24/x
  3. Step 3: Cross multiply
    780.36x = 1,170.80 × 318.24
  4. Step 4: Simplify right side
    780.36x = 372,595.39
  5. Step 5: Solve for x
    x = 372,595.39/780.36
  6. Step 6: Final answer
    x = 477.47

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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.