Answer:
x = 4
Explanation:
The smaller triangle is an equilateral triangle, so all sides and angles are the same. We know that one side is labeled as 5, so all sides of that little triangle are 5.
The bigger triangle is an isosceles triangle because those two angles are marked as congruent. So, line JM and line KM are congruent as well.
The little triangle and the big triangle share side KM, so KM is equal to 5.
If JM is equal to KM and KM is equal to 5, JM is also five. That means:
x + 1 = 5
Subtract 1 from each side.
x = 4
And there we go.