tolong hitung no. 7-10 ya kak

7.)
Jarak antar titik pusat = 16 + 13 +11 = 40 cm
GSPD = √(40² - (13 + 11)²) = √(40² - 24²) = 32 cm (B.)

8.)
Jarak pusat² = GSPD² + (R + r)²
(R + r)² = Jarak pusat² - GSPD²
(R + r)² = 20² - 16²
(R + r) = 12

Perb. jari-jari = 1:3
12 = 3x + x
12 = 4x
x = 3

R = 3x = 3(3) = 9
r = x = 3
(C.)

9.)
Jarak pusat² = GSPD² + (R + r)²
(3r)² = 12² + (r + r - 1)²
9r² = 144 + (2r-1)²
9r² = 144 + (4r² - 4r + 1)
5r² + 4r - 145 = 0
(5r + 29)(r - 5) = 0
r = 5 (D.)

10.)
Jarak pusat² = GSPL² + (R - r)²
26² = 24² + (R - r)²
(R - r)² = 26² - 24²
R - r = 10
R - 15 = 10
r = 25cm (E.)

^^