6 cm, C. He did not square the length of the given leg
Explanation
to solve this we need to use the Pythagorean theorem
T.P states for all rigth triangles:
[tex]a^2+b^2=c^2[/tex]
then
Step 1
let
a=2.3
b=b
c=6.4
replace
[tex]\begin{gathered} 2.3^2+b^2=6.4^2 \\ \text{now, we n}eed\text{ isolate b} \\ 5.29+b^2=40.96 \\ \text{subtract 5.29 in both sides} \\ 5.29+b^2-5.29=40.96-5.29 \\ b^2=35.67 \\ \text{square root in both sides} \\ \sqrt[]{b^2}=\sqrt[]{35.67} \\ b=5.97 \\ \text{rounded} \\ b=6 \end{gathered}[/tex]
Step 2
What mistake might the student have made?
check
A)He added the two given values
[tex]2.3+6.4=8.7[/tex]
B) He subtracted the two given values
[tex]6.4-2.3=4.1[/tex]
C)He did not square the length of the given leg
[tex]\begin{gathered} 2.3^{}+b^2=6.4^2 \\ b^2=6.4^2-2.3 \\ b^2=38.66 \\ b=\sqrt[]{38.66} \\ b=6.21 \\ \text{rounded} \\ b=6.2 \end{gathered}[/tex]
D. He did not square the length of the hypotenuse
[tex]\begin{gathered} 2.3^2+b^2^{}=6.4 \\ b^2=6.4-2.3^2 \\ b^2=1.11 \\ b=\sqrt[]{1.11} \\ b=1.05 \end{gathered}[/tex]
so, the answer is C
I hope this helps you
