Answer:
£59.25
Step-by-step explanation:
Finding the cost
i will put my full working then you will be able to spot where you went wrong
area of a trapezium
formula :
1/2 * ( sumof parallel sides ) * height
= 1/2 * (12 +20 )* h
since height is not given we need to use Pythagoras theorem
right angle triangle
c^2 = a^2 + b^2
17^2 = a^2 + (20-12 )^2
17^2 = a^2+ 8^2
a^2 = 17^2 - 8^2
a^2 = 225
a = 15
height = 15 cm
trapezium area , include the height amount:
1/2 * ( 12 + 20 )* 15
=240 m^2
since 1 can can cover 100 m^2
we can use cross multiplication to find out the amount of cans used :
1 : 100
x : 240
240 = 100x
x = 240/100
x = 2.4
rounded off is 3 cans
hence we need 3 cans
3 * 19.75
= £59.25
hence the only issue you had was putting 2.4 cans. you can not buy 2.4 cans but only 3 cans.
hence you will have to multiple 19.75 * 3 = 59.25 . that was your error
