Question

The sides OP and RO of triangle POR are produced to points S and T respectively. If ∠SPR = 145° and ∠POT = 115° , find ∠PRO

Answer 1

Answer:

$\angle PRQ = 80$

Step-by-step explanation:

Given

$\angle SPR = 145^o$

$\angle POT = 115^o$

See attachment

Required

Find $\angle PRO$

First, calculate $\angle RPO$

$\angle RPO + \angle SPR = 180$ --- angle on a straight line

So, we have:

$\angle RPO + 145 = 180$

Collect like terms

$\angle RPO = 180 - 145$

$\angle RPO = 35$

Next, calculate PQR

$\angle POR + \angle POT = 180$

So, we have:

$\angle POR + 115 = 180$

Collect like terms

$\angle POR = 180-115$

$\angle POR = 65$

So, PRO is calculated as:

$\angle PRO + \angle POR + \angle RPO = 180$ --- angles in a triangle

So, we have:

$\angle PRO + 65 + 35= 180$

$\angle PRO + 100= 180$

Collect like terms

$\angle PRO = 180-100$

$\angle PRO = 80$