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Finding the Fourth Proportional to 771.72, 1,065.20 and 509.80

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Solution

The fourth proportional to 771.72, 1,065.20 and 509.80 is: 703.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.72 : 1,065.20 = 509.80 : x
  2. Step 2: Convert to fraction form
    771.72/1,065.20 = 509.80/x
  3. Step 3: Cross multiply
    771.72x = 1,065.20 × 509.80
  4. Step 4: Simplify right side
    771.72x = 543,038.96
  5. Step 5: Solve for x
    x = 543,038.96/771.72
  6. Step 6: Final answer
    x = 703.67

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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.