Answer:
The dotted line is 4.9
Step-by-step explanation:
The lower triangle is a right triangle so we can use the Pythagorean theorem
a^2+b^2 = c^2
where a and b are the legs and c is the hypotenuse
2^2 + 4^2 = c^2
4+16 = c^2
20 =c^2
Taking the square root of each side
sqrt(20) = c
The upper rectangle has a length of sqrt(20) and a height of 2
We can use the Pythagorean theorem
a^2+b^2 = c^2
where a and b are the legs and c is the hypotenuse to find the diagonal
2^2 + (sqrt(20))^2 = c^2
4+20 = c^2
24 = c^2
Taking the square root of each side
sqrt(24) = c
4.898979486=c
Rounding to the nearest tenth
4.9 =c