In $\bigtriangleup$ PQR, PQ = 10cm, QR = 8cm and RP = 6cm, the perpendicular RS is drawn from R to PQ. Find the length of RS

4cm

32cm

$\frac{30}{7}$

$\frac{40}{7}$

4.8cm

Correct answer is E

Cos Q = $\frac{r^2 + p^2 - q^2}{2rp}$

= $\frac{10^2 + 8^2 - 6^2}{2(10)(8)}$

= $\frac{164 - 36}{160}$

= $\frac{128}{160}$

= 0.8

Q = Cos^-1 o.8

= 37^o x rep. from rt< RSQ, Let RS = x

$\frac{x}{sin 37^o}$ = $\frac{8}{sin 90^o}$

but sin 90^o = 1

x = 8 sin 37^o

x = 4.8cm

See all Mathematics questions & answers

See more JAMB questions & answers

In $\bigtriangleup$ PQR, PQ = 10cm, QR = 8cm and RP = 6cm, the perpendicular RS is drawn from R to PQ. Find the length of RS

Similar Questions

Aptitude Tests

In △\bigtriangleupPQR, PQ = 10cm, QR = 8cm and RP = 6cm, the perpendicular RS is drawn from R to PQ. Find the length of RS

Similar Questions

Aptitude Tests

In $\bigtriangleup$ PQR, PQ = 10cm, QR = 8cm and RP = 6cm, the perpendicular RS is drawn from R to PQ. Find the length of RS