You put $400 in an account. The account earns $18 simple interest in nine months. What is the annual interest rate
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Answer:
BD = 35
Step-by-step explanation:
Calculate CD in right triangle ABC, then BD in right triangle BCD
Using Pythagoras' identity in both triangles.
The square on the hypotenuse is equal to the sum of the squares on the other two sides.
In Δ ADC
CD² + AD² = AC² , substitute values
CD² + 9² = 15²
CD² + 81 = 225 ( subtract 81 from both sides )
CD = 144 ( take the square root of both sides )
CD = = 12
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In Δ BCD
BD² + CD² = BC² , substitute values
BD² + 12² = 37²
BD² + 144 = 1369 ( subtract 144 from both sides )
BD² = 1225 ( take the square root of both sides )
BD = = 35