Answer:
x = 5 cm
Area = 56 cm²
Explanation:
The perimeter of the triangle is given as : 21 cm
The two sides given are : 6 cm and 10 cm. The other side has a length of ;
21 - {6+10} = 21 - 16 = 5 cm
This means the value of x is 5 cm
The rectangle will now have its measurements as ;
Length = 7 cm
Width = x + 3 = 5+3 = 8 cm
The area of the rectangle will be :
A = l * w = 7 * 8 = 56 cm