Answer:
1
Step-by-step explanation:
None of the sides are equal. Isosceles means that 2 sides are equal. Equilateral means that all sides are equal.
Probability is calculated by comparing the odds to a certain event occurring to the number of possible events.
P=

For example, take a six-sided dice number 1-6 on each side. The probability of rolling a 4 would be1 in 6 or 1/6. This is because of the six possible outcomes, rolling a 4 is only one of them.
P(4)=1/6
Now take the same dice. The probability of rolling an even number is 3/6. To see why, lets look at the total possible outcomes:
1
23
45
6
Of the 6 possibilities, 3 are even numbers.
P(even)=3/6 or 1/2
Answer: 25
Assuming the dotted line touches the middle of the base of the triangle,
Using Pythagoras Theorem,
(30/2)^2 + (20)^2 = x^2
x^2 = (15)^2 + 400
x^2 = 625
x = √625 or -(√625)
x = 25 or -25
But since x needs to be a positive value,
x = 25