Answer:
The 1st choice
Explanation:
(a) the first and second ones are the only triangles with all three acute angles. The 2nd one has more than 1 line of symmetry so the 1st must be the answer.
(b) This one really depends on which side of the triangle is each length. One way to do it is A squared + B squared = C squared. 8 equals c because it is the largest side and 7.5 is A. This would be put out like 56.25 + B = 64. Subtract 56.25 from both sides to get B = 7.75.
OR, if 8 is not the longest side 7.5 squared + 8 squared = C squared which would be 120.25 = C squared. So, you would find the square root of 120.25 which is 10.97.