Answer:
28 yards
Step-by-step explanation:
this is a right angled triangle
this question will be solved by Pythagoras theorem
which states square of hypotenuse=square of legs
so 35= 21sqr+b sqr
1225=441+b sqr
b sqr= 1225-441
b sqr=784
b= sqr root of 784
= 28 yards
perimeter=1/2multiplied to base to height
=(21*35)/2
= 367.5
