<em>AC bisects ∠BAD, => ∠BAC=∠CAD ..... (1)</em>
<em>thus in ΔABC and ΔADC, ∠ABC=∠ADC (given), </em>
<em> ∠BAC=∠CAD [from (1)],</em>
<em>AC (opposite side side of ∠ABC) = AC (opposite side side of ∠ADC), the common side between ΔABC and ΔADC</em>
<em>Hence, by AAS axiom, ΔABC ≅ ΔADC,</em>
<em>Therefore, BC (opposite side side of ∠BAC) = DC (opposite side side of ∠CAD), since (1)</em>
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Hence, BC=DC proved.
Their profit made will be 4,420
This is because 0.60 x 1300 is 780
And the amount they will make by selling is $5200, because 1300 x 4
So we will do 5200 - 780, and that is the profit made- $4,420
B+c/d=a subtract b from both sides
c/d=a-b multiply both sides by d
c=d(a-b) or if you prefer
c=ad-bd
Note: if you meant a=(b+c)/d, multiply both sides by d
b+c=ad subtract b from both sides
c=ad-b