Question

Practice
Base of a triangle is 9 and height is 5. Base of
another triangle is 10 and height is 6. Find the
ratio of areas of these triangles.
​

Answer 1

area of 1st triangle= 1/2×b×h

=1/2×9×5

=22.5

area of 2nd triangle= 1/2×b×h

=1/2×10×6

=30

ratio=22.5:30=3:4

Answer 2

A n s w e r

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G i v e n

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• Base of 1st triangle is 9 and height is 5

• Base of 2nd triangle is 10 and height is 6

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F i n d

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• Ratio of areas of these triangle

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S o l u t i o n

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We know that area of a triangle can be found as :

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➠ $\sf \dfrac { 1 } { 2 } \times Base \times Height$ ⚊⚊⚊⚊ ⓵

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$\underline{\bold{\texttt{For 1st triangle :}}}$

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• Base = 9

• Height = 5

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⟮ Putting the above values in ⓵ ⟯

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➜ $\sf \dfrac { 1 } { 2 } \times Base \times Height$

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➜ $\sf \dfrac { 1 } { 2 } \times 9 \times 5$

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➜ $\sf \dfrac { 1 } { 2 } \times 45$

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➜ 22.5 units ⚊⚊⚊⚊ ⓶

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• Hence the area of 1st triangle is 22.5 units

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$\underline{\bold{\texttt{For 2nd triangle :}}}$

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• Base = 10

• Height = 6

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⟮ Putting the above values in ⓵ ⟯

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➜ $\sf \dfrac { 1 } { 2 } \times Base \times Height$

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➜ $\sf \dfrac { 1 } { 2 } \times 10 \times 6$

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➜ $\sf \dfrac { 1 } { 2 } \times 60$

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➜ 30 units ⚊⚊⚊⚊ ⓷

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• Hence the area of 2nd triangle is 30 units

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$\underline{\bold{\texttt{Ratio of areas of these triangles :}}}$

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⟮ From ⓶ & ⓷ ⟯

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➜ $\sf \dfrac { 22.5 } { 30 }$

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➜ $\sf \dfrac { 225 } { 300}$

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➜ $\sf \dfrac { 3 } { 4 }$

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Or,

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➨ 3:4

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• Hence the ratio of areas of these triangles is 3:4