The lengths of AB and CD must be equal to 19 inches.
The oars must be approximately 67.857 inches long.
How to determine missing lengths of oars
In this problem we find a model of oars with some known linear dimensions and we are asked to determine another linear dimensions. The first part consists in knowing the length of oarlocks by taking advantage of symmetry properties.
Based on all the information shown, we can represent the system by the following formula:
AC + AD + DB = 42
x + 4 + x = 42
2 · x = 38
x = 19
The lengths of AB and CD must be equal to 19 inches.
In the second part we must determine the length of a oar, based on the following relationship of proportionality:
AB / EF = 7 / 25
Where AB is the inboard part was found in the previous section, whose measure is 19 inches. Then, we find the length of the oar by using the following formula:
EF = (25 / 7) · AB
EF = (25 / 7) · (19 in)
EF ≈ 67.857 in
The oars must be approximately 67.857 inches long.
To learn more on lengths: https://brainly.com/question/8552546
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