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Finding the Fourth Proportional to 818.72, 1,128.75 and 678.32

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Solution

The fourth proportional to 818.72, 1,128.75 and 678.32 is: 935.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.72 : 1,128.75 = 678.32 : x
  2. Step 2: Convert to fraction form
    818.72/1,128.75 = 678.32/x
  3. Step 3: Cross multiply
    818.72x = 1,128.75 × 678.32
  4. Step 4: Simplify right side
    818.72x = 765,653.70
  5. Step 5: Solve for x
    x = 765,653.70/818.72
  6. Step 6: Final answer
    x = 935.18

Related Problems

Find fourth proportional to 409.36, 564.38 and 339.16
Half scale
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Double scale
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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.