Aregular decagon has a side length of 4 centimeters long if the decagon is divided into 10 congruent triangles each has an approximate height of 6.2 centimeters what is the approximate area of the decagon

Area of decagon is given by:
Area=1/2(nsr)
where:
n=number of sides
s=side length
r=height
thus the area will be given by:
Area=1/2(10*4*6.2)
Area=124 cm^2

Once you know the height and width, multiply them to get the area of the square. To find the perimeter of the square, add all four sides together. To find the area of a triangle, multiply together two of the sides not the hypotenuse and then multiply that figure by 1/2.