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Finding the Fourth Proportional to 780.32, 1,074.48 and 718.40

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Solution

The fourth proportional to 780.32, 1,074.48 and 718.40 is: 989.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.32 : 1,074.48 = 718.40 : x
  2. Step 2: Convert to fraction form
    780.32/1,074.48 = 718.40/x
  3. Step 3: Cross multiply
    780.32x = 1,074.48 × 718.40
  4. Step 4: Simplify right side
    780.32x = 771,906.43
  5. Step 5: Solve for x
    x = 771,906.43/780.32
  6. Step 6: Final answer
    x = 989.22

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.