20m^2, et sa largeur est de 4 m. Quelle est sa longueur? (d) rectangle est de a) 5m b) 10 m c) 15 m d) 20 m 17)Sitaire d'un triangle est de 30cm^2 et que sa base est de 10 cm, quelle est sa hauteur? a) 3cm b) 6 cm c) 9cm d) 12cm

## Step 1: Calculate the length of the rectangle<br />### The area of a rectangle is given by the formula $Area = length \times width$. We are given the area ($20m^2$) and the width (4m). We can rearrange the formula to find the length: $length = \frac{Area}{width}$. Substituting the given values, we get $length = \frac{20}{4} = 5m$.<br />## Step 2: Calculate the height of the triangle<br />### The area of a triangle is given by the formula $Area = \frac{1}{2} \times base \times height$. We are given the area ($30cm^2$) and the base (10cm). We can rearrange the formula to find the height: $height = \frac{2 \times Area}{base}$. Substituting the given values, we get $height = \frac{2 \times 30}{10} = 6cm$.