First find the length of the conclusion by tripling the length of the introduction: 450 words * 3 = <<450*3=1350>>1350 words
Then subtract the length of the introduction and conclusion from the total length to find the combined length of the body sections: 5000 words - 1350 words - 450 words = <<5000-1350-450=3200>>3200 words
Then divide the combined length of the body section by the number of body sections to find the length of each section: 3200 words / 4 sections = <<3200/4=800>>800 words/section
#### 800