Answer:

Step-by-step explanation:
we know that
An isosceles triangle has two equal sides and two equal angles
The two equal angles are called the base angles and the third angle is called the vertex angle
In this problem the triangle ABC is an isosceles triangle
so



The sum of the internal angles of a triangle is equal to 
so
Find the value of y




Solution
Part 3
For this case we have 6 different terms
Part 4
We can do the following:

Part 5
And we can simplify on this way:

Answer:
400cm²
Step-by-step explanation:
Total surface area of a prism includes the area of the top and bottom triangle sides of the prism, plus the area of all 3 rectangular sides.
Base & Bottom triangle area: 2 x [(8 x 15)/2] = 120cm²
Side triangle area: 17 x 7 + 8 x 7 + 15 x 7 = 280cm²
Total surface area = 280 + 120 = 400cm²
Answer:
okay so do 20-5=15 then divide how much each ticket costs and you get the answer.