In the figure, the line segment ST is tangent to two circles at S and…

Home » Past Questions » Mathematics » Jamb » 1993 » In the figure, the line segment ST is tangent to two circles at S and…
Mathematics JAMB 1993

In the figure, the line segment ST is tangent to two circles at S and T. O and Q are the centres of the circles wih OS = 5cm. QT = 2cm and OR = 14cm. Find ST

  • 7 \(\sqrt{3}\)cm
  • 12.9cm checkmark
  • \(\sqrt{87}\)cm
  • 7cm

The correct answer is: B

Explanation

SQ2 + OS2 = OQ2 + 52 = 142

SQ2 = 142 - 52

196 - 25 = 171

ST2 + TQ2 = SQ2

ST2 + 22 = 171

ST2 = 171 - 4

= 167

ST = \(\sqrt{167}\)

= 12.92 = 12.9cm
Previous Question Next Question

Leave A Comment