P = (a + b + c) * 1/2 = (14 + 14 +14) * 1/2 = 21 cм S = sqrt(p(p - a)(p - b)(p - c) S = sqrt(21 * 7 * 7 * 7) = 49sqrt(3) см^2 S = abc/4R => R = abc/4S R = 14 * 14 * 14/49sqrt(3) = 56/sqrt(3) см S = pr => r = S/p r = 49sqrt(3)/21 = 7sqrt(3)/3 = 7/sqrt(3) см
S = sqrt(p(p - a)(p - b)(p - c)
S = sqrt(21 * 7 * 7 * 7) = 49sqrt(3) см^2
S = abc/4R => R = abc/4S
R = 14 * 14 * 14/49sqrt(3) = 56/sqrt(3) см
S = pr => r = S/p
r = 49sqrt(3)/21 = 7sqrt(3)/3 = 7/sqrt(3) см