Great! Now that you understand the structure of the perceptron, here’s an important question — how are the inputs and weights magically turned into an output? This is a two-step process, and the first step is *finding the weighted sum of the inputs*.

What is the **weighted sum**? This is just a number that gives a reasonable representation of the inputs:

`$weighted\ sum = x_1w_1 + x_2w_2 + ... + x_nw_n$`

The *x*‘s are the inputs and the *w*‘s are the weights.

Here’s how we can implement it:

- Start with a weighted sum of 0. Let’s call it
`weighted_sum`

. - Start with the first input and multiply it by its corresponding weight. Add this result to
`weighted_sum`

. - Go to the next input and multiply it by its corresponding weight. Add this result to
`weighted_sum`

. - Repeat this process for all inputs.

### Instructions

**1.**

Create a variable called `weighted_sum`

to hold the value of the weighted sum and set its starting value to `0`

.

Return `weighted_sum`

outside the `for`

loop.

**2.**

Let’s go through each input-weight pair and find the weighted sum using indexing.

Delete the `pass`

statement inside the `for`

loop. For each iteration in the loop, find the product of the input and weight at index `i`

, add the result to `weighted_sum`

, and store it back in `weighted_sum`

to update the value of `weighted_sum`

.

**3.**

Outside the `Perceptron`

class, after the `Perceptron`

object `cool_perceptron`

has been created, print out the weighted sum for the inputs `[24, 55]`

.

What is the weighted sum?

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