(b) Sides of a triangle a = 5 cm, b = 12 cm and c = 13 cm s =
a+b+c
2
=
5+12+13
2
=
30
2
= 15 Area of triangle = √s(s−a)(s−b)(s−c) = √15(15−5)(15−12)(15−13) = √15×10×3×2 = √5×3×5×2×3×2 = √5×5×3×3×2×2 = 5 x 3 x 2 = 30 cm2 Area of rectangle = Area of triangle Hence, area of rectangle = 30 cm2 Width of rectangle = 10 cm Area of rectangle = Length x Width 30 = l x 10 ∴ l = 3 cm Perimeter of rectangle =2(l + W) = 2(35+ 10) =2 x 13 = 26 cm