You can focus on the two sub-triangles ABC and ACD
We know that they are both right triangles, because we're given that AC and BD are perpendicular.
The sides AB and AD are the hypothenuses of these triangles, so we know their length through the pythagorean theorem:


But since we're given
, the expressions for AD and AB are actually the same expression. This proves that AD=AB, and thus that the triangle is isosceles.
Hello! Let's work this problem from left to right to make things a bit easier ;)
6.5+(-2) is the same as 6.5-2, since adding a negative is the same as subtracting a positive. 6.5-2=4.5
Now, we have to add 10.5 to 4.5, which gives us the grand total of 15. I hope this helped! Let me know if you need anything else!
Answer:
The answer is

Step-by-step explanation:
Remember that Taylor says that

For this case


Answer:b
Step-by-step explanation:it equals out to 180°