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Finding the Fourth Proportional to 661.20, 913.32 and 645.36

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Solution

The fourth proportional to 661.20, 913.32 and 645.36 is: 891.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.20 : 913.32 = 645.36 : x
  2. Step 2: Convert to fraction form
    661.20/913.32 = 645.36/x
  3. Step 3: Cross multiply
    661.20x = 913.32 × 645.36
  4. Step 4: Simplify right side
    661.20x = 589,420.20
  5. Step 5: Solve for x
    x = 589,420.20/661.20
  6. Step 6: Final answer
    x = 891.44

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Double scale
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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.