Answer:
Perimeter = 36 cm
Step-by-step explanation:
Ratio of sides = 5:4:3
Sides are:
a = 5x ; b= 4x ; c = 3x
Semi perimeter S = (a + b+ c )/2 = (5x + 4x +3x)/2 = 12x /2 = 6x
S - a = 6x - 5x = x
S - b = 6x - 4x = 2x
S - c = 6x - 3x = 3x
[tex]Area=\sqrt{S*(S-a)*(S-b)*(S-c)}\\\\\sqrt{6x*x*2x*3x}=54\\\\\sqrt{36x^{4}}=54\\\\6x^{2}=54\\\\x^{2}=\frac{54}{6}\\\\x^{2}=9\\\\x=\sqrt{9}\\\\ x=3\\[/tex]
sides of triangle:
a = 5x = 5*3 = 15 cm
b = 4x = 4*3 = 12 cm
c = 3x = 3*3 = 9 cm
Perimeter = 15 + 12 + 9 = 36 cm
