Convex lens has a diameter of 30mm and a depth of 5mm at the center. How far from the vertex is the focus.

Translate the word phrase into a math expression. 15 fewer than the product of 4 and a number. (pls immediately)

What three-dimensional solid have 6 rectangular faces, 2 equal bases that are not rectangles and 18 edges

Will mark brainliest for correct answer! i have been on this problem for an hour and can't find the answer. i'm begging here! incase you cant read the instructions in the picture because of too much or too little lighting: note: enter your answer and show all the steps that you use to solve this problem in the space provided.write a list of steps that are needed to find the measure of b. provide all steps as clear as possible, !