Tolong dong jawab no 7,8,9,10 aja pliss

7) L = [tex] \pi r^{2} [/tex]
1386 = [tex] \frac{22}{7} [/tex] x [tex] r^{2} [/tex]
[tex] r^{2} [/tex] = 1386 : [tex] \frac{22}{7} [/tex]
[tex]r^{2} [/tex] = 441
r = [tex] \sqrt{441} [/tex]
r = 21 cm

7.) L=22/7 × r × r
1386=22/7 × r × r
1386 × 7/22=r×r
441=r^2
21=r

8.) K=2×22/7 ×7
K=44 cm
jarak= 44 × 80
=3520 cm = 35,2 meter

9.) Larsir=Lpersegi - L1/4lingkaran
=(15 × 15) - (1/4 × 3,14 × 15^2)
=225 - 176,625
=48,375 cm2

10.) 45° + 20° = 75°
<pusat=<keliling×2
=75×2
=150°

(maaf kalo salah)