The card states that it serves 10 people. How much flour is required to make enough bread for 30 people?

4.5 C

Step-by-step explanation:

10x 3 =30

1.5 c × 3 =4.5

In ΔABC and Δ DEC:

∠ABC = ∠DEC (both angles are 90 degrees )

We can see that the angles, ∠ABC and ∠DEC are corresponding angles

Since the corresponding angles are equal, we can say that:  AB || DE

In ΔABC and Δ DEC:

∠ABC = ∠DEC  (Both are 90 degrees)

∠ACB = ∠ECD  (Common angle)

Hence, by the AA criterion, we can say that ΔABC ≈ Δ DEC

Finding the Ratio of Similarity:

From the triangle, we see that:

BC = 12 units

EC = 7 units

Since the triangles are similar, they have a constant ratio between their sides

Ratio of sides of  ΔABC and Δ DEC = BC / EC

Ratio = 12 / 7

Finding h:

We can see that the sides AB and DE are similar, we also know the ratio of similarity between the sides

We can say that:

h * ratio of similarity = AB

h * 12/7 = 9

h = 63 / 12

h = 5.25 units