Jawaban sama caranya no 18 apa?

Jawaban sama caranya no 18 apa?

Maaf yg c itu berapa angkanya?
aku jawab misalkan itu 28
K= a+b+c
K= 21+35+28
K= 84

${a}^{2} + {b}^{2} = {c}^{2}$
${a}^{2} + {21}^{2} = {35}^{2}$
${a}^{2} + 441 = 1225$
${a}^{2} = 1225 - 441$
${a}^{2} = 784$
$a = sqrt{784}$
$a = 28$
$keliling : = a + b + c$
$28 + 21 + 35$
$b.84$