Can atriangle be formed with side lengths of 5cm. 10cm and 15cm

2 answers:

6 0

Remember
longest side must be less than the sum of the other 2 sides because if it is eqal than you get a line, and if it is longer, then you cannot connect the points

longest side is 15
15<10+5
15<15
fasle

no triangle can be formed

andreyandreev [35.5K]4 years ago

3 0

Theorem of cosine:
a²=b²+c²-2bc(cos α) ⇒cos α=-(a²-b²-c²) / 2bc

In this case:
a=15 cm
b=10 cm
c=5 cm

cos α=-(15²-10²-5²) / 2*10*5
cos α=-100 / 100
cos α=-1

A=arc cos -1=180º This is impossible, because:

A+B+C=180º; then B=C=0º This is impossible for make a triangle (B>0 and C>0 if we want to make a triangle).

Therefore: it is not possible can make a triangle with side lengths of 5 cm, 10 cm and 15 cm.

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Erin feeds her dog 7/10 cup of food a day . With 3/10 cup canned and the rest dry . She also gives her dog 1 treat a day . How m

gavmur [86]

Answer:

$2\frac{4}{5}\ \ or \ 2.8 \ \ cups$

Step-by-step explanation:

-The total portion fed to the dog is 7/10 cup

Canned-3/10
Dry=7/10-3/10=4/10

-One week has 7 days. we multiply the dry portion per day by the number of days in a week.

$Dry= Total -Canned\\\\=\frac{7}{10}-\frac{3}{10}\\\\=0.40 \ cup\\\\Dry \ per \ Week= Dry/ day\times days\\\\=0.40\times 7\\\\=2\frac{4}{5}\ or\ 2.8 \ cups$