One of the angles formed by two intersecting straight lines is 90 degrees. What are the others equal to?

Since when two straight lines intersect, four corners are formed. They are pairwise equal to each other, because these are two pairs of vertical angles. Since we know the value of one angle, we find its vertical, it is also equal to 90 °.

The rest of the angles are adjacent to those given to us in the condition, therefore, we subtract 90 ° from 180: 180 – 90 = 90 °. Hence, the remaining angles are equal to 90 °.

Answer: 90, 90, 90, 90.