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Finding the Fourth Proportional to 660.58, 911.51 and 380.75

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Solution

The fourth proportional to 660.58, 911.51 and 380.75 is: 525.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.58 : 911.51 = 380.75 : x
  2. Step 2: Convert to fraction form
    660.58/911.51 = 380.75/x
  3. Step 3: Cross multiply
    660.58x = 911.51 × 380.75
  4. Step 4: Simplify right side
    660.58x = 347,057.43
  5. Step 5: Solve for x
    x = 347,057.43/660.58
  6. Step 6: Final answer
    x = 525.38

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Half scale
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Double scale
Find fourth proportional to 661.58, 912.89 and 381.75
Similar ratio
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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.