Are angles 1 and 4 linear pair, vertical angles or neither? you! : )

Determine which expressions represent real numbers and which expressions represent complex number. asaaap! plis!

Circle a has a diameter of 7 inches, a circumference of 21.98 inches, and an area of 38.465 square inches. the diameter of circle b is 6 inches, the circumference is 18.84 inches, and the area is 28.26 square inches. part a: using the formula for circumference, solve for the value of pi for each circle. (4 points) part b: use the formula for area and solve for the value of pi for each circle. (4 points)

Two numbers have a sum of -19. one number is x. what expression represents the other number?