Kathya is buying edging for a triangular
flower garden she plans to build in her
backyard. If the lengths of the three pieces of
edging that she purchases are 13 feet, 10 feet,
and 7 feet, will the flower garden be in the
shape of a right triangle?

No those exact sides create a 86 degree it would decrease by 2 degree every 2x 0.2 measure change as seen below.

Step-by-step explanation:

Given a=7.4 and b=10.4 if these sides were less then so would the hypotenuse slant be less so as 7.4 and 10.4 shows 12.76 hypotenuse

hypotenuse = 12.76401

then anything showing 7 feet with 10feet can only be right angle if hypotenuse slant was 12.21 feet maximum. As Pythagoras shows 12.20656 x 12.20656 = √149.000107034 = 7^2 + 10^2

This proves measure triangle measure of  7 and 10 = 12.2 maximum to make a right angle.

the answer is a beach is the best place to be