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Finding the Fourth Proportional to 660.45, 911.55 and 380.87

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Solution

The fourth proportional to 660.45, 911.55 and 380.87 is: 525.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.45 : 911.55 = 380.87 : x
  2. Step 2: Convert to fraction form
    660.45/911.55 = 380.87/x
  3. Step 3: Cross multiply
    660.45x = 911.55 × 380.87
  4. Step 4: Simplify right side
    660.45x = 347,182.34
  5. Step 5: Solve for x
    x = 347,182.34/660.45
  6. Step 6: Final answer
    x = 525.67

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1.5x scale

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.