Find the length of OB and AC
Show working out

Answer:
OB = AC = sqrt(13)
Step-by-step explanation:
OB² = OA² + AB²
OB² = 3² + 2² = 9 + 4
OB² = 13
OB = sqrt(13)
AC = OB (diagonals of a rectangle are equal in length)
Answer:
√13 units
Step-by-step explanation:
Use this equation. This rectangle is made up of two right triangles, so you can use the Pythagorean theorem.
Considering this is a rectangle, OB and AC should be the same value. Let's use the right bottom triangle to solve this.
You know from the graph the values of a and b.
Line OA is 3 units long, and Line AB is 2 units long.
These 2 values are your a and b, so just plug them into the equation.
set c² equal to 13.
To get rid of the square sign, square root both sides of the equation. The square sign gets canceled out and this is your answer.