The height of the heater is about 89.3 in.
Step By Step Explanation:
You can solve this problem with the Pythagorean Theorem. The base is a square. So half way across the middle will the right under the tip of the pyramid. We can use the measurement with the slant height to write and solve the equation below.
23.8^2 + x^2 = 90.1^2
x will be about 89.3.