Let's solve the problem step by step based on the provided image and text.

Given Data:

1. Total area of the property: 6.24 are = $624 \, \text{m}^2$.
2. Grass seed information:
   • 1 kg of grass seed covers $50 \, \text{m}^2$.
   • Cost of 1 kg of grass seed: €20.60.
   • 15% discount is available today.
3. Grass area dimensions:
   • The grass zone is divided into a rectangle ($11 \, \text{m} \times 18 \, \text{m}$) and a smaller triangle.

Step 1: Calculate the area of the grass zone

1. Area of the rectangle: $\text{Area}_{\text{rectangle}} = 11 \, \text{m} \times 18 \, \text{m} = 198 \, \text{m}^2$

2. Area of the triangle (top part): $\text{Area}_{\text{triangle}} = \frac{1}{2} \times 5 \, \text{m} \times 11 \, \text{m} = 27.5 \, \text{m}^2$

3. Total grass area: $\text{Total Grass Area} = 198 \, \text{m}^2 + 27.5 \, \text{m}^2 = 225.5 \, \text{m}^2$

Step 2: Calculate the number of kilograms of grass seed needed

Each kilogram covers $50 \, \text{m}^2$. The required kilograms are: $\text{Kilograms of seed} = \frac{225.5}{50} = 4.51 \, \text{kg}$ Since we can't buy a fraction of a kilogram, round up to $5 \, \text{kg}$.

Step 3: Calculate the cost of grass seed

1. Cost before discount: $\text{Cost} = 5 \, \text{kg} \times 20.60 \, \text{€/kg} = 103.00 \, \text{€}$

2. Cost after 15% discount: $\text{Discounted Cost} = 103.00 \, \text{€} \times (1 - 0.15) = 103.00 \, \text{€} \times 0.85 = 87.55 \, \text{€}$

Final Answer:

The cost to sow the grass is €87.55.

Would you like a detailed explanation of any step or additional examples?

Here are 5 related questions for practice:

1. What is the cost without the 15% discount?
2. How much grass seed would you need if the total area was 300 $\text{m}^2$?
3. How would the cost change if the discount was 20%?
4. What if only the rectangle portion of the grass area was to be planted? What would be the cost?
5. If the price per kg of grass seed increased to €25, what would the new total cost be?

Tip: Always round up when dealing with quantities that cannot be fractional, like kilograms in this problem!