Question #59194

2 Answers
Feb 4, 2018

As explainedenter image source here

Explanation:

Since triangles ABC & AQR are similar,

#(AQ )/ (AB) = (AR) / (AC) = (QR) / (BC)#

Also #AhatBC = AhatQR = 60^0#

But AQ = AB * 1.5 = 5 * 1.5 = 7.5 cm#

From the diagram,
BC = (CD) / sin 60 = 3 / (sqrt3/2) = 2 sqrt3 = 3.4641#

QR = (BC) * 1.5 = 3.4641 * 1.5 = 5.196 cm#

Now we know two sides AQ, QR and included angle #hatQ#

Now we can construct #Delta AQR#

Feb 4, 2018

drawn

Steps for construction

  1. Line segments of length 5cm and 3cm are drawn with the help of a ruler.
  2. A line segment #AX# of length #> 8cm # is also drawn similarly.
  3. Line segment #AB# is then cut off from AX with the help of a compass.
  4. #/_ABK=60^@# is drawn with the help of a ruler and a compass.
  5. With the help of a ruler and a compass a perpendicular #AN# on #AB# at #A# is drawn and an intercept #AP=3cm# is cut off with the help of a compass.
  6. #PO# is drawn parallel to #AB# with the help of a compass and a ruler. #PO# intersects #BK# at #C#. #A and C# are joined . The #DeltaABC# is the required triangle having altitude #CD=3cm#.
  7. #AB# is bisected at #E# with the help of a compass and a ruler.
  8. Line segment #BQ=BE# is cut off from extended part of #AB# to make #AQ=1.5xxAB#.
  9. #/_AQL=60^@# is drawn to get get #QL"||"BC#. This QL intersects extended #AC# at #R#.
  10. Now #DeltaAQR# is the similar to #DeltaABC# having #1.5# times of the corresponding sides of #DeltaABC#.