please help me withthis thanks

Answer:
[tex]\huge\boxed{A=168\ cm^2}[/tex]
Step-by-step explanation:
[tex]A=\dfrac{d_1\times d_2}{2}\\\\d_1,\ d_2-\text{diagonals of a kite}\\\\\text{We have:}\\\\d_1=8cm+8cm=16cm\\\\d_2=6cm+15cm=21cm\\\\\text{Substitute:}\\\\A=\dfrac{(16)(21)}{2}=\dfrac{336}{2}=168\ cm^2[/tex]