Use the Pythagorean theorem two times:
[tex]NQ^2+NP^2=QP^2\\\\36^2+h^2=39^2\\\\1296+h^2=1521\qquad\text{subtract 1521 from both sides}\\\\h^2=225\to h=\sqrt{225}\\\\\boxed{h=15\ cm}[/tex]
second time:
[tex]PR^2=RN^2+NP^2\\\\x^2=8^2+15^2\\\\x^2=64+225\\\\x^2=289\to x=\sqrt{289}\\\\\boxed{x=17\ cm}[/tex]
Answer:
17 cm
Step-by-step explanation:
We must first find the length of the height, PN. Since PN is an altitude, it makes a right angle with QR; this means that PNQ will be a right triangle, as will PNR. This means we will use the Pythagorean theorem:
a²+b² = c²
Letting h represent PR (since it is the height),
h²+36² = 39²
h²+1296 = 1521
Subtract 1296 from each side:
h²+1296-1296 = 1521-1296
h² = 225
Take the square root of each side:
√(h²) = √(225)
h = 15
PN is 15 cm.
Now we will use it and the other "base," RN, to find PR:
15²+8² = x²
225+64 = x²
289 = x²
Take the square root of each side:
√(289) = √(x²)
17 = x
