tolong di jawab no 1, terimakasih

a) l² = j² - (r1 - r)²
12² = 13² - (r1 - 3,5)²
144 = 169 - (r1 - 3,5)²
(r1 - 3,5)² = 169 - 144
(r1 - 3,5)² = 25
r1 - 3,5 = √25
r1 - 3,5 = 5
r1 = 5 + 3,5
r1 = 8,5 cm

b) d² = j² - (r1 + r2)²
d² = 13² - (8,5 + 3,5)²
d² = 169 - 12²
d² = 169 - 144
d² = 25
d = √25
d = 5 cm

maaf klw salah, semoga membantu :)