Use the atof() function to convert a string representation of the float number to a float number.
Screenshots of code are nearly worthless. If you want more help read the forum guidelines to see how to properly post code and some information on how to get the most from this forum.
Use the IDE autoformat tool (ctrl-t or Tools, Auto format) before posting code in code tags.
Please include the entire error message. It is easy to do. There is a button (lower right of the IDE window) called "copy error message". Copy the error and paste into a post in code tags. Paraphrasing the error message leaves out important information.
Please fix your original post.