Answer: Any isosceles triangle is a counter example. More specifically, a triangle with sides 7, 7 and 3
When forming your triangle, make sure you apply the triangle inequality theorem. This is the idea where adding any two sides leads to a result larger than the third side. So we have
7+7 = 14 which is larger than 3
7+3 = 10 which is larger than 7
By definition, an isosceles triangle has two congruent sides. Some books say "at least 2 congruent sides", but I'll go with the first definition. If you want all three sides to be congruent, then you'd go for the term "equilateral".
2x^2 - 8 = 0
2x^2 = 8
x^2 = 8/2 = 4
x = sqrt(4) = 2 or -2
Let S be the amount in a savings account.
Let m be the number of months.
General equation
S = 132 + 27m
Specific question
July is the 7th month of the year including both January and July.
S = 132 + 7*27
S = 132 + 189
S = 321
Reasonableness?
Good question. You could estimate an answer.
Start with 150 dollars and say that you add 25 a month.
7 * 25 = 175
S = 150 + 175 = 325 All of this was done in my head. Since the exact answer obtained using the formula is 321, I think that's pretty reasonable using my estimate is a guide.
