ini gimana ya tolong ya pake jalannya

8. A. 38cm
    Keliling Persegi Panjang     = 7cm + 10cm + 10cm = 27cm
    Keliling setengah lingkaran = [tex] \pi X r = \frac{22}{7} X 3,5cm = 11cm[/tex]
    Keliling bangun No. 22 = 27cm + 11 cm = 38cm


9. D. 792[tex] cm^{2} [/tex]
    Luas layang-layang = [tex] \frac{1}{2} [/tex] x D1 x D2
                                    = [tex] \frac{1}{2} [/tex] x (14cm+30cm) x (18cm+18cm)
                                    = [tex] \frac{1}{2} [/tex] x  44cm x 36cm
                                    = [tex] \frac{1}{2} [/tex] x  1.584cm
                                    = 792[tex] cm^{2} [/tex]