create a problem similar to the one your classmate has created in

Topic 19: Finding a Missing side in a 45°, 45°, 90° special Triangle

Dependent on which side is missing will determine your equation.  The  ratio you want to remember is x, x, x√2 which √2=1.4, so if you are  missing a leg side in an isosceles triangle the base angles are the same  so both leg sides will be the same.  Using the value of a side you can  figure the hypotenuse side by X√2.  If only given the Hypotenuse side,  we must divide by √2 so X√2/√2 which will equal X your leg sides and  they will be the same.  Given the hypotenuse side we must divide by the  √2 and then we rationalize multiplying that √2/√2 and simplifying from  there.  Topic 19 Examples.pdfDownload Topic 19 Examples.pdf 

References

Tutoring, M. M. (2016, Febuary 22). 45-45-90 Special Right Triangles. Retrieved from YouTube: https://www.youtube.com/watch?v=nQEqpVK7ZPA