Given: △ABC, BC>AC, D∈ AC , CD=CB Prove: m∠ABD is acute
1 answer:
Answer:
Step-by-step explanation:
Given: △ABC, BC>AC, D∈ AC , CD=CB
To prove: m∠ABD is acute
Proof: In ΔABC, the angle opposite to side BC is ∠BAC and the angle opposite to side AC is ∠ABC.
Now, it is given that BC>AC, then ∠BAC>∠ABC.. (1)
In ΔBDC, using the exterior angle property,
∠ADB=∠DBC+∠BCD
∠ADB=∠DBC+∠BCA
⇒∠ADB>∠BAC (2)
From equation (1) and (2), we get
∠ADB>∠BAC
⇒∠ADB>∠ABC
⇒DB>AB
Hence, m∠ABD is acute
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b. length: 11 and width: x
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d. length: 16x and width: 1
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<u>Rectangle (a)</u>
<u>Rectangle (b)</u>
<u>Rectangle (c)</u>
<u>Rectangle (d)</u>
Rectangles (a), (c) and (d) have the same area (i.e. 16x) while rectangle (b) has 11x as its area.
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