Step-by-step explanation:
1.
[tex]a = \frac{1}{2} b \times h \\ \frac{1}{2} \times 8 \times 7 \\ a = 4 \times 7 = 28 {cm}^{2} [/tex]
2.
[tex]a = \frac{1}{2} b \times h \\ a = \frac{1}{2} \times 10 \times 10 \\ a = 10 \times 5 = 50 {ft}^{2} [/tex]
