Answer:
90
Step-by-step explanation:
Given: Measure of one side of equilateral triangle = 
Measure of another side of equilateral triangle = 
In equilateral triangle all three sides are equal in length.Therefore,
On substituting the value of x in side of equilateral triangle,
One side of equilateral triangle = 
Perimeter of equilateral triangle = 3 ( length of one side) ........( given)
perimeter of equilateral triangle = 
Well first you could multiply things to see what gets you to 213
Answer:
Step-by-step explanation:
When learning about commutative and associative properties, we learn that ...
a + b = b + a . . . . . addition is commutative
ab = ba . . . . . . . . . multiplication is commutative
But we also know that ...
a - b ≠ b - a . . . . . . subtraction is not commutative
a/b ≠ b/a . . . . . . . . division is not commutative
__
We also learn that ...
a + (b+c) = (a+b) +c . . . . addition is associative
a(bc) = (ab)c . . . . . multiplication is associative
And of course, ...
a - (b -c) ≠ (a -b) -c . . . . subtraction is not associative
a/(b/c) ≠ (a/b)/c . . . . . . . division is not associative
_____
However, you can use associative and commutative properties in problems involving subtraction and division if you write the expression properly:
a - (b - c) = a +(-(b -c)) = a +((-b) +c) = (a +(-b)) +c . . . . keeping the sign with the value makes it an addition problem, so the associative property can apply
(a/b)/c = (a(1/b))(1/c) = a(1/b·1/c) = writing the division as multiplication by a reciprocal makes it so the associative property can apply
