In ΔABC, given that b = 40cm and c = 25cm, and angle A = 20˚, find the length of side a.
2006-12-16 15:15:01 · 5 answers · asked by thomasgraham880 1 in Science & Mathematics ➔ Mathematics
a=18.6 approximately. use Law of Cosines.
Steve
2006-12-16 15:20:28 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Using Law of Cosines
a^2 = b^2 + c^2 - 2bc(cosA)
a^2 = 40^2 + 25^2 - 2(40 * 25)cos(20)
a^2 = 1600 + 625 - 2(1000)cos(20)
a^2 = 2225 - 2000cos(20)
a = about 18.59cm
2006-12-16 16:36:19 · answer #2 · answered by Sherman81 6 · 1⤊ 0⤋
Use the law of cosines.
a^2 = b^2 + c^2 - 2bc cos A
a^2 = 40^2 + 25^2 - 2*40*25 cos 20°
= 1600 + 625 - 2000 cos 20°
= 2225 - 2000 cos 20°
a = sqrt(2225 - 2000 cos 20°) = 18.59
2006-12-16 15:23:22 · answer #3 · answered by Northstar 7 · 1⤊ 0⤋
Applying cosine rule,
a² = b² + c² - 2bc cos A
a² = 40² + 25² - 2(40)(25)cos20°
a² = 345.6148
a = 18.6cm
2006-12-17 04:41:08 · answer #4 · answered by Ranna Renni 2 · 1⤊ 0⤋
the two deffently. regardless of ways lots magic is in it, it surely relies upon on hom lots which you will attain with that magic. And in case you dont have any magic the dimensions doesnt subject rely the two.
2016-10-15 02:29:11 · answer #5 · answered by Anonymous · 0⤊ 0⤋