Question

One side of the bottom layer of a triangular pyramid has 11 balls. How many are there in the whole pyramid? Note that the pyramid is equilateral and solid.

Answer 1

Answer:

Step-by-step explanation:

Equilateral

Answer 2

Step-by-step explanation:

Given one side of bottom layer of triangular pyramid has 11 balls so there are 11 layers of balls.   How many are there in the whole pyramid? Note that the pyramid is equilateral and solid.

• So the first layer has 1 ball
• Second layer will have 3 (1 + 2) balls
• The Third layer will have 6(1 + 2 + 3) balls.
• Fourth layer has 10(1 + 2 + 3 + 4) balls.
• Fifth layer will have 15(1 + 2 + 3 + 4 + 5) balls
• Similarly there are 21(1 + 2 + 3 + 4 + 5 + 6) balls
• So there will be 28,36,45,55 and 66 balls in the remaining layers.
• So total number of balls will be 1 + 3 + 6 + 10 + 15 + 21 + 28 + 36 + 45 + 55 + 66 = 286 balls.

Reference link will be

https://brainly.in/question/18626868