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Finding the Fourth Proportional to 780.64, 1,170.20 and 698.63

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Solution

The fourth proportional to 780.64, 1,170.20 and 698.63 is: 1,047.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.64 : 1,170.20 = 698.63 : x
  2. Step 2: Convert to fraction form
    780.64/1,170.20 = 698.63/x
  3. Step 3: Cross multiply
    780.64x = 1,170.20 × 698.63
  4. Step 4: Simplify right side
    780.64x = 817,528.79
  5. Step 5: Solve for x
    x = 817,528.79/780.64
  6. Step 6: Final answer
    x = 1,047.26

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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.