Answer:
Step-by-step explanation:
The shape above is a trapezium, and the area of a trapezium can be calculated using
A = ½(a + b)h
Where, a and b is the two parallel line
Then, a = 12 and b = 20,
We need to find the height by applying Pythagoras theorem to triangle ABC
AC² = AB² + BC². Check attachment
a² = b² + c²
17² = 8² + h²
h² = 17² - 8²
h² = 289 - 64
h² = 225
h = √225
h = 15m
So, the area of the trapezium
A = ½(a + b)h
A = ½ × (12 + 20) × 15
A = ½ × 32 × 15
A = 16 × 15
A = 240m²
Given that, 100m² can be cover with one can
100m² = 1 can
100 m² = 1 can
240m² = x
Cross multiply
100 m² × x = 1 can × 240m²
divide both sides 100m²
x = 1 can × 240m² / 100m²
x = 2.4 can
So, we need 2.4 cans weed killer
Then, given that 1 can cost £19.75
1 can = £19.75
2.4 cans = 2.4 × £19.75
2.4 cans = £47.4
The cost of the weed killer is £47.4