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Finding the Fourth Proportional to 780, 1,071.60 and 655.44

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Solution

The fourth proportional to 780, 1,071.60 and 655.44 is: 900.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    780 : 1,071.60 = 655.44 : x
  2. Step 2: Convert to fraction form
    780/1,071.60 = 655.44/x
  3. Step 3: Cross multiply
    780x = 1,071.60 × 655.44
  4. Step 4: Simplify right side
    780x = 702,369.50
  5. Step 5: Solve for x
    x = 702,369.50/780
  6. Step 6: Final answer
    x = 900.47

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.