Answer:
39°
sum of triangle's interior angles: 180°
180°-90°-51°=39°
Answer:
1
or

Step-by-step explanation:
Let the number be n
Part A- 2/3 + n = 2n+3
Part B- n= 2/3 -3
n= 2-9 / 3
n= -7/3 =-2.33
Answer:
A. at least two congruent sides
Step-by-step explanation:
Since, we know that,
'An isosceles triangle is a triangle having two sides of equal length or at least two sides of equal length (special case is equilateral triangle)'.
Thus, from the options, we see that,
Options B, C and D are not correct.
<em>Since, congruent sides means that the lengths of the sides are equal.</em>
Thus, we get that,
'An isosceles triangle has at least two congruent sides'.
Hence, option A is correct.
I think d but i might be wrong :( sorry