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Finding the Fourth Proportional to 860.42, 1,290.64 and 347.78

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Solution

The fourth proportional to 860.42, 1,290.64 and 347.78 is: 521.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.42 : 1,290.64 = 347.78 : x
  2. Step 2: Convert to fraction form
    860.42/1,290.64 = 347.78/x
  3. Step 3: Cross multiply
    860.42x = 1,290.64 × 347.78
  4. Step 4: Simplify right side
    860.42x = 448,858.78
  5. Step 5: Solve for x
    x = 448,858.78/860.42
  6. Step 6: Final answer
    x = 521.67

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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.