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Finding the Fourth Proportional to 815.57, 1,223.35 and 328.51

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Solution

The fourth proportional to 815.57, 1,223.35 and 328.51 is: 492.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.57 : 1,223.35 = 328.51 : x
  2. Step 2: Convert to fraction form
    815.57/1,223.35 = 328.51/x
  3. Step 3: Cross multiply
    815.57x = 1,223.35 × 328.51
  4. Step 4: Simplify right side
    815.57x = 401,878.38
  5. Step 5: Solve for x
    x = 401,878.38/815.57
  6. Step 6: Final answer
    x = 492.76

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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 (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.