The shadow of a post is 6degree longer when the elevation of the sun is 30degree than when it is 60degree calculate the height of the post

answer:

5.196 centimeters.

Step-by-step explanation:

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.