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Answer:
a) ∆ABC ~ ∆EDC by AA similarity
b) ED/AB = 3/4
c) 15 cm
Explanation:
a) Two angles in each triangle are the same, so the AA similarity postulate can be used to declare the ∆ABC ~ ∆EDC. (Each triangle includes a right angle and angle C.)
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b) Corresponding sides are ED/AB, DC/BC, EC/AC. The ratio of corresponding sides is ED/BC = (12 cm)/(16 cm) = 3/4.
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c) Using the ratios identified above, we have ...
DC/BC = 3/4 = x/(20 cm)
x = 3/4(20 cm)
x = 15 cm