Answer:
14.7
Step-by-step explanation:
a^2+b^2=c^2
15^2+b^2=21^2
225+b^2=441
subtract 441-225=216
square root of 216 = 14.6969384567
= 14.7
Answer:
x = 6[tex]\sqrt{6}[/tex]
Step-by-step explanation:
Using Pythagoras' identity in the right triangle.
The square on the hypotenuse is equal to the sum of the squares on the other two sides, that is
x² + 15² = 21²
x² + 225 = 441 ( subtract 225 from both sides )
x² = 216 ( take the square root of both sides )
x = [tex]\sqrt{216}[/tex] = [tex]\sqrt{36(6)}[/tex] = [tex]\sqrt{36}[/tex] × [tex]\sqrt{6}[/tex] = 6[tex]\sqrt{6}[/tex]
