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Finding the Fourth Proportional to 816.72, 1,125.72 and 661.20

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Solution

The fourth proportional to 816.72, 1,125.72 and 661.20 is: 911.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.72 : 1,125.72 = 661.20 : x
  2. Step 2: Convert to fraction form
    816.72/1,125.72 = 661.20/x
  3. Step 3: Cross multiply
    816.72x = 1,125.72 × 661.20
  4. Step 4: Simplify right side
    816.72x = 744,326.06
  5. Step 5: Solve for x
    x = 744,326.06/816.72
  6. Step 6: Final answer
    x = 911.36

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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.