Answer:
19
Explanation:
The square value of the measure of hypotenuse is equal to the square measure of sum of two legs.
Let x represent the missing leg:

400 = 49 + x^2 subtract 49 from both sides
351 = x^2 find the root for both sides
The root of 351 is between 18 and 19 but it is closer to 19 since 19×19 = 361 and since we are asked to round to the nearest tenth the answer is 19.