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Finding the Fourth Proportional to 811.56, 1,116.36 and 678.72

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Solution

The fourth proportional to 811.56, 1,116.36 and 678.72 is: 933.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.56 : 1,116.36 = 678.72 : x
  2. Step 2: Convert to fraction form
    811.56/1,116.36 = 678.72/x
  3. Step 3: Cross multiply
    811.56x = 1,116.36 × 678.72
  4. Step 4: Simplify right side
    811.56x = 757,695.86
  5. Step 5: Solve for x
    x = 757,695.86/811.56
  6. Step 6: Final answer
    x = 933.63

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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.