Answer:
Area = 370 m²
Cost to paint = £105
Step-by-step explanation:
Area of the wall of a cinema hall = Area of a trapezoid (1)+ Area of a rectangle (2) + Area of a trapezoid (3)
Area of a trapezoid = [tex]\frac{1}{2}(b_1+b_2)h[/tex]
where [tex]b_1[/tex] and [tex]b_2[/tex] are the parallel sides and h is the distance between these sides.
Area of trapezoid (1) = [tex]\frac{1}{2}(11+12)\times 6[/tex]
= 69 m²
Area of the rectangle (2) = Length × Width
= 12 × 15
= 180 m²
Area of the trapezoid (3) = [tex]\frac{1}{2}(12+10)\times 11[/tex]
= 121 m²
Now area of the wall = 69 + 180 + 121
= 370 m²
One tin covers the area = 25 m²
Number of tins required to paint the wall = [tex]\frac{\text{Total area}}{\text{Area covered by one tin}}[/tex]
= [tex]\frac{370}{25}[/tex]
= 14.8
Therefore, number of tins to be purchased = 15
Cost to paint the complete wall = 15 × £7
= £105
