Question

area, volume and capacity
topic 3: area of a triangle
question 1 find the area of the following triangles.
a
6 cm
10 cm
b
18 cm
5 cm
c
15 cm
8 cm
d
18 cm
9 cm
e
7 cm
4 cm
f
12 cm
21 cm
question 2

Explanation:

Step1: Recall the formula for the area of a triangle

The formula for the area of a triangle is \( A=\frac{1}{2}\times base\times height\).

Step2: Calculate the area for each triangle

a

For triangle a: \( base = 10\ cm\), \( height=6\ cm\).
\(A=\frac{1}{2}\times10\times6 = 30\ cm^{2}\).

b

For triangle b: \( base = 18\ cm\), \( height = 5\ cm\).
\(A=\frac{1}{2}\times18\times5=45\ cm^{2}\).

c

For triangle c: \( base = 8\ cm\), \( height = 15\ cm\).
\(A=\frac{1}{2}\times8\times15 = 60\ cm^{2}\).

d

For triangle d: \( base = 9\ cm\), \( height = 18\ cm\).
\(A=\frac{1}{2}\times9\times18=81\ cm^{2}\).

e

For triangle e: \( base = 4\ cm\), \( height = 7\ cm\).
\(A=\frac{1}{2}\times4\times7 = 14\ cm^{2}\).

f

For triangle f: \( base = 12\ cm\), \( height = 21\ cm\).
\(A=\frac{1}{2}\times12\times21=126\ cm^{2}\).

Answer:

a. \(30\ cm^{2}\), b. \(45\ cm^{2}\), c. \(60\ cm^{2}\), d. \(81\ cm^{2}\), e. \(14\ cm^{2}\), f. \(126\ cm^{2}\)