Hi there!
We can find the area of a triangle with the formula:

Filling in this formula gives us the following answers.
Triangle 1

Triangle 2

Triangle 3
Answer:
x = y/ (Uk)
Step-by-step explanation:
U = y / xk
Multiply each side by xk
Uxk = y / xk *xk
U xk = y
Divide each side by Uk
U xk/ (Uk) = y/ (Uk)
x = y/ (Uk)
Answer:
The original length of each side of the equilateral triangle = x =15 inches
Step-by-step explanation:
Let Original length of side of equilateral triangle = x
If it is increased by 5 inches, the length will become = x+5
Since in equilateral triangle all the ides have same length so,
New Length of side 1 = x+5
New of side 2 = x+5
New Length of side 3 = x+5
Perimeter of triangle = 60 inches
We need to find the value of x
The formula used is: 
Putting values in formula and finding x

So, the original length of each side of the equilateral triangle = x =15 inches
Let x be the length of one side of the smaller square
Let y be the length of one side of the larger square
4x would be the perimeter of the smaller square, as it has 4 sides
Therefore 4x = y + 10, as the perimeter of the smaller square is 10 inches bigger than one side of the larger square.
We're going to solve this question using simultaneous equations. This means we need another equation to compare the first one to.
Since we know that one side of the larger square is 2 inches bigger than the first one, we can make the equation
y = x + 2
Know that we know the value of y in terms of x, we can introduce this value to the original equation to find:
4x = (x + 2) + 10
Therefore:
4x = x + 12
3x = 12
x = 4
Now that we know the size of the sides on the smaller square, we can figure out the size of the larger square by using our second equation (y = x + 2)
y = 4 + 2
y = 6
Therefore, the length of each side of the larger square is<u> B.6</u>