nomor 7-dan 10ya................

jawab
7)

garis PQ  melalui (0,1) dan (2.3)
x - y = - 1
garis AB tegak lurus PQ melalui (2,3)
x + y = 2 + 3
x + y = 5
titk  A = (0,5)
titik B = (5,0)
Luas = 1/2 (5)(5) = 12,5


10)
K1 -->  r1= 12 ,t1= 12
V1= 1/3 π r²t = 1/3 (12)³ π

K2 --> r2 = 4, t2= ...
r2/r1 = t2/t1
4/12 = t2/12
t2= 4

V2 = 1/3π r² t = 1/3 (4)³ π

V arsiran = V1 - V2 
= 1/3 π {(12)³ -  (4)³ }
= 1/3 π (1.664)
= 554 2/3 π