A father is 60 years old and his son is half his age how old was the boy when his father was four times his age

1 answer:

5 0

F=60, s=60/2=30

(60-x)/(30-x)=4

60-x=120-4x

60+3x=120

3x=60

x=20

s=30-x

s=30-20

s=10

So the boy was 10 years old when his father was four times his age.

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In triangle ABC segment DE is parallel to the side AC . (The endpoints of segment DE lie on the sides AB and BC respectively). F

Sophie [7]

Answer:

The length of DE is 14 cm.

Step-by-step explanation:

Given in triangle ABC segment DE is parallel to the side AC . (The endpoints of segment DE lie on the sides AB and BC respectively). we have to find the length of DE.

Given lengths are AC=20cm, AB=17cm, and BD=11.9cm

In ΔBDE and ΔBAC

∠BDE=∠BAC (∵Corresponding angles)

∠BED=∠BCA (∵Corresponding angles)

By AA similarity rule, ΔBDE~ΔBAC

∴their corresponding sides are in proportion

⇒ $\frac{BE}{BC}=\frac{BD}{BA}=\frac{DE}{AC}$