Diketahui panjang sisi segitiga =4cm,5cm,7cm .berapa panjang jari-jari lingkaran luar

S = 1/2 K
S = 1/2 (4 + 5 + 7)
S = 1/2 (16)
S = 8

L = √{s (s - a)(s - b)(s - c)}
L = √8 (8 - 4)(8 - 5)(8 - 7)
L = √ 8 (4) (3) (1)
L = √ 4 . 2 . 4 . 3
L = 2 . 2 √6
L = 4√6

r = a.b.c / 4L
r = 4.5.7 / 4 (4√6)
r = 35 / 4√6
r = 35 / 9,79
r = 3,57