Alberto and 9 of his friends went out to eat.
1 + 9 = 10
So there are 10 people in total.
Each person paid the same amount, $18.
18 × 10 = 180
The total bill was $180.
It is always isosceles because it can be proved as follows:
The perpendicular bisector dissects the triangle into two, and it is the common side. Then each side of the bisector is 90 degrees, and the bisected to two equal sides, so the two dissected triangles are congruent, hence the original triangle is isosceles.
Answer:
Step-by-step explanation:
If the 4th lies opposite the 11th, then you know the 3rd lies opposite the 10th, the 2nd opposite the 9th, and the 1st opposite the 8th; meanwhile, in the reverse direction you'd find that the 5th lies opposite the 12th, the 6th opposite the 13th, and the 7th opposite the 14th. Move up one more bead and you're back at the 1st, which you already know lies opposite the 8th. Therefore there are 14 total bead