The answer would be standard deviation.
x=9 because the triangle is equilateral which means every side is equal to 60. When you do the math you get 7x-3=60 which is 7x=63 and 63/7=9
To solve for S, you would want to get rid of the denominator so multiply 360 onto both sides. then the equation is 360A=pi times r squared times S. Divide both sides by pi and r squared and you get S=360A/pi times r squared
Answer:
see attachment
Step-by-step explanation:
