Area of a Triangle Questions and Answers - Form 2 Topical Mathematics

Questions

1. The figure below represents a triangular plot ABC. The lengths of AB = 50m, AC = 80m and angle BAC =30^o
   

   

   1. Find the length of BC to 2 s.f
   2. Find the area of the plot in hectares
   3. The plot is fenced using 4 strands of barbed wire. The length of one roll of barbed wire is 600m and it costs shs.4000. Calculate;
      1. The length of fencing wire required
      2. The number of complete rolls to be bought
      3. The cost of the rolls

Answers

1. 1. BC² = 50² + 80² – 2 x 50 x 80 cos30
      = 2500 + 6400 – 6928.20 = 1971.8
      ∴ BC =√1971.8
      = 44.40m
      = 44m
   2. Area of the plot
      = ½ x 50 x 80 x sin30 = 1000m²
      = ¹⁰⁰⁰/₁₀₀₀₀ ha
      = 0.01ha
   3. 1. Length of wire required
         = (50 + 80 + 44) x 4 = 696m
      2. Complete rolls to be bought = 2
      3. Cost (2 x 4000) = Shs.8000