Mohon dibantu Jawaban A.140cm ^2 B. 150 cm^2 C.180 cm^2 D.210cm^2 E.240cm ^2

Materi : Luas segitiga

Keliling = DE + EF + DF
70 = DE + 25 + 17
DE = 70 - 25 - 17
DE = 28 cm

s = 1/2 × keliling
s = 1/2 × 70
s = 35 cm

L ∆ DEF = √[s (s - a)(s - b)(s - c)]
= √[35 (35 - 25)(35 - 17)(35 - 28)]
= √[35 (10)(18)(7)]
= √44100
= 210 cm^2